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Commit 356cbe4f authored by igor@rurik.mysql.com's avatar igor@rurik.mysql.com
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join_nested.test, join_nested.result: 

  new file
Many files:
  Nested joins added.
parent f9e2c6cd
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Showing with 3149 additions and 240 deletions
mysql-test/r/join_nested.result 0 → 100644
View file @ 356cbe4f
DROP TABLE IF EXISTS t0,t1,t2,t3,t4,t5,t6,t7,t8,t9;
Warnings:
Note 1051 Unknown table 't0'
Note 1051 Unknown table 't1'
Note 1051 Unknown table 't2'
Note 1051 Unknown table 't3'
Note 1051 Unknown table 't4'
Note 1051 Unknown table 't5'
Note 1051 Unknown table 't6'
Note 1051 Unknown table 't7'
Note 1051 Unknown table 't8'
Note 1051 Unknown table 't9'
CREATE TABLE t0 (a int, b int, c int);
CREATE TABLE t1 (a int, b int, c int);
CREATE TABLE t2 (a int, b int, c int);
CREATE TABLE t3 (a int, b int, c int);
CREATE TABLE t4 (a int, b int, c int);
CREATE TABLE t5 (a int, b int, c int);
CREATE TABLE t6 (a int, b int, c int);
CREATE TABLE t7 (a int, b int, c int);
CREATE TABLE t8 (a int, b int, c int);
CREATE TABLE t9 (a int, b int, c int);
INSERT INTO t0 VALUES (1,1,0), (1,2,0), (2,2,0);
INSERT INTO t1 VALUES (1,3,0), (2,2,0), (3,2,0);
INSERT INTO t2 VALUES (3,3,0), (4,2,0), (5,3,0);
INSERT INTO t3 VALUES (1,2,0), (2,2,0);
INSERT INTO t4 VALUES (3,2,0), (4,2,0);
INSERT INTO t5 VALUES (3,1,0), (2,2,0), (3,3,0);
INSERT INTO t6 VALUES (3,2,0), (6,2,0), (6,1,0);
INSERT INTO t7 VALUES (1,1,0), (2,2,0);
INSERT INTO t8 VALUES (0,2,0), (1,2,0);
INSERT INTO t9 VALUES (1,1,0), (1,2,0), (3,3,0);
SELECT t2.a,t2.b
FROM t2;
a b
3 3
4 2
5 3
SELECT t3.a,t3.b
FROM t3;
a b
1 2
2 2
SELECT t4.a,t4.b
FROM t4;
a b
3 2
4 2
SELECT t3.a,t3.b,t4.a,t4.b
FROM t3,t4;
a b a b
1 2 3 2
2 2 3 2
1 2 4 2
2 2 4 2
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t2.b=t4.b;
a b a b a b
3 3 NULL NULL NULL NULL
4 2 1 2 3 2
4 2 1 2 4 2
4 2 2 2 3 2
4 2 2 2 4 2
5 3 NULL NULL NULL NULL
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b;
a b a b a b
3 3 NULL NULL NULL NULL
4 2 1 2 3 2
4 2 1 2 4 2
5 3 NULL NULL NULL NULL
EXPLAIN
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t2.b=t4.b
WHERE t3.a=1 OR t3.c IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 3
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 2
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t2.b=t4.b
WHERE t3.a=1 OR t3.c IS NULL;
a b a b a b
3 3 NULL NULL NULL NULL
4 2 1 2 3 2
4 2 1 2 4 2
5 3 NULL NULL NULL NULL
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t2.b=t4.b
WHERE t3.a>1 OR t3.c IS NULL;
a b a b a b
3 3 NULL NULL NULL NULL
4 2 2 2 3 2
4 2 2 2 4 2
5 3 NULL NULL NULL NULL
SELECT t5.a,t5.b
FROM t5;
a b
3 1
2 2
3 3
SELECT t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t3,t4,t5;
a b a b a b
1 2 3 2 3 1
2 2 3 2 3 1
1 2 4 2 3 1
2 2 4 2 3 1
1 2 3 2 2 2
2 2 3 2 2 2
1 2 4 2 2 2
2 2 4 2 2 2
1 2 3 2 3 3
2 2 3 2 3 3
1 2 4 2 3 3
2 2 4 2 3 3
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t2
LEFT JOIN
(t3, t4, t5)
ON t2.b=t4.b;
a b a b a b a b
3 3 NULL NULL NULL NULL NULL NULL
4 2 1 2 3 2 3 1
4 2 1 2 3 2 2 2
4 2 1 2 3 2 3 3
4 2 1 2 4 2 3 1
4 2 1 2 4 2 2 2
4 2 1 2 4 2 3 3
4 2 2 2 3 2 3 1
4 2 2 2 3 2 2 2
4 2 2 2 3 2 3 3
4 2 2 2 4 2 3 1
4 2 2 2 4 2 2 2
4 2 2 2 4 2 3 3
5 3 NULL NULL NULL NULL NULL NULL
EXPLAIN
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t2
LEFT JOIN
(t3, t4, t5)
ON t2.b=t4.b
WHERE t3.a>1 OR t3.c IS NULL;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 3
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 2
1 SIMPLE t5 ALL NULL NULL NULL NULL 3
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t2
LEFT JOIN
(t3, t4, t5)
ON t2.b=t4.b
WHERE t3.a>1 OR t3.c IS NULL;
a b a b a b a b
3 3 NULL NULL NULL NULL NULL NULL
4 2 2 2 3 2 3 1
4 2 2 2 3 2 2 2
4 2 2 2 3 2 3 3
4 2 2 2 4 2 3 1
4 2 2 2 4 2 2 2
4 2 2 2 4 2 3 3
5 3 NULL NULL NULL NULL NULL NULL
EXPLAIN
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t2
LEFT JOIN
(t3, t4, t5)
ON t2.b=t4.b
WHERE (t3.a>1 OR t3.c IS NULL) AND
(t5.a<3 OR t5.c IS NULL);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 3
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 2
1 SIMPLE t5 ALL NULL NULL NULL NULL 3 Using where
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t2
LEFT JOIN
(t3, t4, t5)
ON t2.b=t4.b
WHERE (t3.a>1 OR t3.c IS NULL) AND
(t5.a<3 OR t5.c IS NULL);
a b a b a b a b
3 3 NULL NULL NULL NULL NULL NULL
4 2 2 2 3 2 2 2
4 2 2 2 4 2 2 2
5 3 NULL NULL NULL NULL NULL NULL
SELECT t6.a,t6.b
FROM t6;
a b
3 2
6 2
6 1
SELECT t7.a,t7.b
FROM t7;
a b
1 1
2 2
SELECT t6.a,t6.b,t7.a,t7.b
FROM t6,t7;
a b a b
3 2 1 1
6 2 1 1
6 1 1 1
3 2 2 2
6 2 2 2
6 1 2 2
SELECT t8.a,t8.b
FROM t8;
a b
0 2
1 2
EXPLAIN
SELECT t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t6 ALL NULL NULL NULL NULL 3
1 SIMPLE t7 ALL NULL NULL NULL NULL 2
1 SIMPLE t8 ALL NULL NULL NULL NULL 2
SELECT t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10;
a b a b a b
3 2 1 1 NULL NULL
6 2 1 1 NULL NULL
6 1 1 1 NULL NULL
3 2 2 2 0 2
3 2 2 2 1 2
6 2 2 2 0 2
6 2 2 2 1 2
6 1 2 2 0 2
6 1 2 2 1 2
SELECT t5.a,t5.b
FROM t5;
a b
3 1
2 2
3 3
SELECT t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b;
a b a b a b a b
3 1 3 2 1 1 NULL NULL
3 1 6 2 1 1 NULL NULL
2 2 3 2 2 2 0 2
2 2 3 2 2 2 1 2
2 2 6 2 2 2 0 2
2 2 6 2 2 2 1 2
3 3 NULL NULL NULL NULL NULL NULL
SELECT t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b AND
(t8.a < 1 OR t8.c IS NULL);
a b a b a b a b
3 1 3 2 1 1 NULL NULL
3 1 6 2 1 1 NULL NULL
2 2 3 2 2 2 0 2
2 2 6 2 2 2 0 2
3 3 NULL NULL NULL NULL NULL NULL
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b;
a b a b a b
3 3 NULL NULL NULL NULL
4 2 1 2 3 2
4 2 1 2 4 2
5 3 NULL NULL NULL NULL
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b;
a b a b a b a b a b a b a b
3 3 NULL NULL NULL NULL 3 1 3 2 1 1 NULL NULL
3 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL
4 2 1 2 3 2 3 1 3 2 1 1 NULL NULL
4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL
4 2 1 2 4 2 3 1 3 2 1 1 NULL NULL
4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL
5 3 NULL NULL NULL NULL 3 1 3 2 1 1 NULL NULL
5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL
3 3 NULL NULL NULL NULL 2 2 3 2 2 2 0 2
3 3 NULL NULL NULL NULL 2 2 3 2 2 2 1 2
3 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2
3 3 NULL NULL NULL NULL 2 2 6 2 2 2 1 2
4 2 1 2 3 2 2 2 3 2 2 2 0 2
4 2 1 2 3 2 2 2 3 2 2 2 1 2
4 2 1 2 3 2 2 2 6 2 2 2 0 2
4 2 1 2 3 2 2 2 6 2 2 2 1 2
4 2 1 2 4 2 2 2 3 2 2 2 0 2
4 2 1 2 4 2 2 2 3 2 2 2 1 2
4 2 1 2 4 2 2 2 6 2 2 2 0 2
4 2 1 2 4 2 2 2 6 2 2 2 1 2
5 3 NULL NULL NULL NULL 2 2 3 2 2 2 0 2
5 3 NULL NULL NULL NULL 2 2 3 2 2 2 1 2
5 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2
5 3 NULL NULL NULL NULL 2 2 6 2 2 2 1 2
3 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL
4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL
4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL
5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
WHERE t2.a > 3 AND
(t6.a < 6 OR t6.c IS NULL);
a b a b a b a b a b a b a b
4 2 1 2 3 2 3 1 3 2 1 1 NULL NULL
4 2 1 2 4 2 3 1 3 2 1 1 NULL NULL
5 3 NULL NULL NULL NULL 3 1 3 2 1 1 NULL NULL
4 2 1 2 3 2 2 2 3 2 2 2 0 2
4 2 1 2 3 2 2 2 3 2 2 2 1 2
4 2 1 2 4 2 2 2 3 2 2 2 0 2
4 2 1 2 4 2 2 2 3 2 2 2 1 2
5 3 NULL NULL NULL NULL 2 2 3 2 2 2 0 2
5 3 NULL NULL NULL NULL 2 2 3 2 2 2 1 2
4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL
4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL
5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL
SELECT t1.a,t1.b
FROM t1;
a b
1 3
2 2
3 2
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2);
a b a b a b a b a b a b a b a b
1 3 3 3 NULL NULL NULL NULL 3 1 3 2 1 1 NULL NULL
1 3 3 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL
1 3 3 3 NULL NULL NULL NULL 2 2 3 2 2 2 0 2
1 3 3 3 NULL NULL NULL NULL 2 2 3 2 2 2 1 2
1 3 3 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2
1 3 3 3 NULL NULL NULL NULL 2 2 6 2 2 2 1 2
1 3 3 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL
1 3 4 2 1 2 3 2 3 1 3 2 1 1 NULL NULL
1 3 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL
1 3 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL
1 3 4 2 1 2 4 2 3 1 3 2 1 1 NULL NULL
1 3 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL
1 3 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL
1 3 5 3 NULL NULL NULL NULL 3 1 3 2 1 1 NULL NULL
1 3 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL
1 3 5 3 NULL NULL NULL NULL 2 2 3 2 2 2 0 2
1 3 5 3 NULL NULL NULL NULL 2 2 3 2 2 2 1 2
1 3 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2
1 3 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 1 2
1 3 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL
2 2 NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL
3 2 3 3 NULL NULL NULL NULL 3 1 3 2 1 1 NULL NULL
3 2 3 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL
3 2 3 3 NULL NULL NULL NULL 2 2 3 2 2 2 0 2
3 2 3 3 NULL NULL NULL NULL 2 2 3 2 2 2 1 2
3 2 3 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2
3 2 3 3 NULL NULL NULL NULL 2 2 6 2 2 2 1 2
3 2 3 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL
3 2 4 2 1 2 3 2 3 1 3 2 1 1 NULL NULL
3 2 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL
3 2 4 2 1 2 3 2 2 2 3 2 2 2 0 2
3 2 4 2 1 2 3 2 2 2 3 2 2 2 1 2
3 2 4 2 1 2 3 2 2 2 6 2 2 2 0 2
3 2 4 2 1 2 3 2 2 2 6 2 2 2 1 2
3 2 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL
3 2 4 2 1 2 4 2 3 1 3 2 1 1 NULL NULL
3 2 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL
3 2 4 2 1 2 4 2 2 2 3 2 2 2 0 2
3 2 4 2 1 2 4 2 2 2 3 2 2 2 1 2
3 2 4 2 1 2 4 2 2 2 6 2 2 2 0 2
3 2 4 2 1 2 4 2 2 2 6 2 2 2 1 2
3 2 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL
3 2 5 3 NULL NULL NULL NULL 3 1 3 2 1 1 NULL NULL
3 2 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL
3 2 5 3 NULL NULL NULL NULL 2 2 3 2 2 2 0 2
3 2 5 3 NULL NULL NULL NULL 2 2 3 2 2 2 1 2
3 2 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2
3 2 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 1 2
3 2 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2)
WHERE (t2.a >= 4 OR t2.c IS NULL);
a b a b a b a b a b a b a b a b
1 3 4 2 1 2 3 2 3 1 3 2 1 1 NULL NULL
1 3 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL
1 3 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL
1 3 4 2 1 2 4 2 3 1 3 2 1 1 NULL NULL
1 3 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL
1 3 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL
1 3 5 3 NULL NULL NULL NULL 3 1 3 2 1 1 NULL NULL
1 3 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL
1 3 5 3 NULL NULL NULL NULL 2 2 3 2 2 2 0 2
1 3 5 3 NULL NULL NULL NULL 2 2 3 2 2 2 1 2
1 3 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2
1 3 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 1 2
1 3 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL
2 2 NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL
3 2 4 2 1 2 3 2 3 1 3 2 1 1 NULL NULL
3 2 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL
3 2 4 2 1 2 3 2 2 2 3 2 2 2 0 2
3 2 4 2 1 2 3 2 2 2 3 2 2 2 1 2
3 2 4 2 1 2 3 2 2 2 6 2 2 2 0 2
3 2 4 2 1 2 3 2 2 2 6 2 2 2 1 2
3 2 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL
3 2 4 2 1 2 4 2 3 1 3 2 1 1 NULL NULL
3 2 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL
3 2 4 2 1 2 4 2 2 2 3 2 2 2 0 2
3 2 4 2 1 2 4 2 2 2 3 2 2 2 1 2
3 2 4 2 1 2 4 2 2 2 6 2 2 2 0 2
3 2 4 2 1 2 4 2 2 2 6 2 2 2 1 2
3 2 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL
3 2 5 3 NULL NULL NULL NULL 3 1 3 2 1 1 NULL NULL
3 2 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL
3 2 5 3 NULL NULL NULL NULL 2 2 3 2 2 2 0 2
3 2 5 3 NULL NULL NULL NULL 2 2 3 2 2 2 1 2
3 2 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2
3 2 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 1 2
3 2 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL
SELECT t0.a,t0.b
FROM t0;
a b
1 1
1 2
2 2
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2)
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t3 ALL NULL NULL NULL NULL 2
1 SIMPLE t4 ALL NULL NULL NULL NULL 2
1 SIMPLE t5 ALL NULL NULL NULL NULL 3
1 SIMPLE t7 ALL NULL NULL NULL NULL 2
1 SIMPLE t6 ALL NULL NULL NULL NULL 3
1 SIMPLE t8 ALL NULL NULL NULL NULL 2
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2)
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL);
a b a b a b a b a b a b a b a b a b
1 2 2 2 NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL
1 2 3 2 4 2 1 2 3 2 3 1 3 2 1 1 NULL NULL
1 2 3 2 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL
1 2 3 2 4 2 1 2 3 2 2 2 3 2 2 2 0 2
1 2 3 2 4 2 1 2 3 2 2 2 3 2 2 2 1 2
1 2 3 2 4 2 1 2 3 2 2 2 6 2 2 2 0 2
1 2 3 2 4 2 1 2 3 2 2 2 6 2 2 2 1 2
1 2 3 2 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL
1 2 3 2 4 2 1 2 4 2 3 1 3 2 1 1 NULL NULL
1 2 3 2 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL
1 2 3 2 4 2 1 2 4 2 2 2 3 2 2 2 0 2
1 2 3 2 4 2 1 2 4 2 2 2 3 2 2 2 1 2
1 2 3 2 4 2 1 2 4 2 2 2 6 2 2 2 0 2
1 2 3 2 4 2 1 2 4 2 2 2 6 2 2 2 1 2
1 2 3 2 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL
1 2 3 2 5 3 NULL NULL NULL NULL 3 1 3 2 1 1 NULL NULL
1 2 3 2 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL
1 2 3 2 5 3 NULL NULL NULL NULL 2 2 3 2 2 2 0 2
1 2 3 2 5 3 NULL NULL NULL NULL 2 2 3 2 2 2 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2
1 2 3 2 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t5 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t7 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t6 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t8 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t9 ALL NULL NULL NULL NULL 3 Using where
SELECT t9.a,t9.b
FROM t9;
a b
1 1
1 2
3 3
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
a b a b a b a b a b a b a b a b a b a b
1 2 2 2 NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL 1 1
1 2 3 2 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL 1 1
1 2 3 2 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL 1 1
1 2 3 2 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL 1 1
1 2 3 2 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL 1 1
1 2 3 2 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL 1 1
1 2 3 2 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL 1 1
1 2 2 2 NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL 1 2
1 2 3 2 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL 1 2
1 2 3 2 4 2 1 2 3 2 2 2 6 2 2 2 0 2 1 2
1 2 3 2 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL 1 2
1 2 3 2 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL 1 2
1 2 3 2 4 2 1 2 4 2 2 2 6 2 2 2 0 2 1 2
1 2 3 2 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL 1 2
SELECT t1.a,t1.b
FROM t1;
a b
1 3
2 2
3 2
SELECT t2.a,t2.b
FROM t2;
a b
3 3
4 2
5 3
SELECT t3.a,t3.b
FROM t3;
a b
1 2
2 2
SELECT t2.a,t2.b,t3.a,t3.b
FROM t2
LEFT JOIN
t3
ON t2.b=t3.b;
a b a b
3 3 NULL NULL
4 2 1 2
4 2 2 2
5 3 NULL NULL
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b
FROM t1, t2
LEFT JOIN
t3
ON t2.b=t3.b
WHERE t1.a <= 2;
a b a b a b
1 3 3 3 NULL NULL
2 2 3 3 NULL NULL
1 3 4 2 1 2
1 3 4 2 2 2
2 2 4 2 1 2
2 2 4 2 2 2
1 3 5 3 NULL NULL
2 2 5 3 NULL NULL
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b
FROM t1, t3
RIGHT JOIN
t2
ON t2.b=t3.b
WHERE t1.a <= 2;
a b a b a b
1 3 3 3 NULL NULL
2 2 3 3 NULL NULL
1 3 4 2 1 2
1 3 4 2 2 2
2 2 4 2 1 2
2 2 4 2 2 2
1 3 5 3 NULL NULL
2 2 5 3 NULL NULL
SELECT t3.a,t3.b,t4.a,t4.b
FROM t3,t4;
a b a b
1 2 3 2
2 2 3 2
1 2 4 2
2 2 4 2
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b;
a b a b a b
3 3 NULL NULL NULL NULL
4 2 1 2 3 2
4 2 1 2 4 2
5 3 NULL NULL NULL NULL
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t1, t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b
WHERE t1.a <= 2;
a b a b a b a b
1 3 3 3 NULL NULL NULL NULL
2 2 3 3 NULL NULL NULL NULL
1 3 4 2 1 2 3 2
1 3 4 2 1 2 4 2
2 2 4 2 1 2 3 2
2 2 4 2 1 2 4 2
1 3 5 3 NULL NULL NULL NULL
2 2 5 3 NULL NULL NULL NULL
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t1, (t3, t4)
RIGHT JOIN
t2
ON t3.a=1 AND t2.b=t4.b
WHERE t1.a <= 2;
a b a b a b a b
1 3 3 3 NULL NULL NULL NULL
2 2 3 3 NULL NULL NULL NULL
1 3 4 2 1 2 3 2
1 3 4 2 1 2 4 2
2 2 4 2 1 2 3 2
2 2 4 2 1 2 4 2
1 3 5 3 NULL NULL NULL NULL
2 2 5 3 NULL NULL NULL NULL
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t1, t3, t4
RIGHT JOIN
t2
ON t3.a=1 AND t2.b=t4.b
WHERE t1.a <= 2;
a b a b a b a b
1 3 3 3 1 2 NULL NULL
2 2 3 3 1 2 NULL NULL
1 3 3 3 2 2 NULL NULL
2 2 3 3 2 2 NULL NULL
1 3 4 2 1 2 3 2
1 3 4 2 1 2 4 2
2 2 4 2 1 2 3 2
2 2 4 2 1 2 4 2
1 3 4 2 2 2 NULL NULL
2 2 4 2 2 2 NULL NULL
1 3 5 3 1 2 NULL NULL
2 2 5 3 1 2 NULL NULL
1 3 5 3 2 2 NULL NULL
2 2 5 3 2 2 NULL NULL
CREATE INDEX idx_b ON t2(b);
EXPLAIN
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t3,t4
LEFT JOIN
(t1,t2)
ON t3.a=1 AND t3.b=t2.b AND t2.b=t4.b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 ALL NULL NULL NULL NULL 2
1 SIMPLE t4 ALL NULL NULL NULL NULL 2
1 SIMPLE t2 ref idx_b idx_b 5 test.t3.b 2
1 SIMPLE t1 ALL NULL NULL NULL NULL 3
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t3,t4
LEFT JOIN
(t1,t2)
ON t3.a=1 AND t3.b=t2.b AND t2.b=t4.b;
a b a b a b
4 2 1 2 3 2
4 2 1 2 3 2
4 2 1 2 3 2
NULL NULL 2 2 3 2
4 2 1 2 4 2
4 2 1 2 4 2
4 2 1 2 4 2
NULL NULL 2 2 4 2
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t4 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t5 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t7 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t6 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t8 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t9 ALL NULL NULL NULL NULL 3 Using where
CREATE INDEX idx_b ON t4(b);
CREATE INDEX idx_b ON t5(b);
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t4 ref idx_b idx_b 5 test.t2.b 2 Using where
1 SIMPLE t5 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t7 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t6 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t8 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t9 ALL NULL NULL NULL NULL 3 Using where
CREATE INDEX idx_b ON t8(b);
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t4 ref idx_b idx_b 5 test.t2.b 2 Using where
1 SIMPLE t5 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t7 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t6 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t8 ref idx_b idx_b 5 test.t7.b 2 Using where
1 SIMPLE t9 ALL NULL NULL NULL NULL 3 Using where
CREATE INDEX idx_b ON t1(b);
CREATE INDEX idx_a ON t0(a);
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ref idx_a idx_a 5 const 1 Using where
1 SIMPLE t1 ref idx_b idx_b 5 test.t0.b 2 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t3 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t4 ref idx_b idx_b 5 test.t2.b 2 Using where
1 SIMPLE t5 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t7 ALL NULL NULL NULL NULL 2 Using where
1 SIMPLE t6 ALL NULL NULL NULL NULL 3 Using where
1 SIMPLE t8 ref idx_b idx_b 5 test.t7.b 2 Using where
1 SIMPLE t9 ALL NULL NULL NULL NULL 3 Using where
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
a b a b a b a b a b a b a b a b a b a b
1 2 2 2 NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL 1 1
1 2 3 2 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL 1 1
1 2 3 2 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL 1 1
1 2 3 2 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL 1 1
1 2 3 2 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL 1 1
1 2 3 2 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL 1 1
1 2 3 2 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL 1 1
1 2 2 2 NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL 1 2
1 2 3 2 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL 1 2
1 2 3 2 4 2 1 2 3 2 2 2 6 2 2 2 0 2 1 2
1 2 3 2 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL 1 2
1 2 3 2 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL 1 2
1 2 3 2 4 2 1 2 4 2 2 2 6 2 2 2 0 2 1 2
1 2 3 2 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL 1 2
SELECT t2.a,t2.b
FROM t2;
a b
3 3
4 2
5 3
SELECT t3.a,t3.b
FROM t3;
a b
1 2
2 2
SELECT t2.a,t2.b,t3.a,t3.b
FROM t2 LEFT JOIN t3 ON t2.b=t3.b
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a IS NULL);
a b a b
4 2 1 2
4 2 2 2
5 3 NULL NULL
SELECT t2.a,t2.b,t3.a,t3.b
FROM t2 LEFT JOIN (t3) ON t2.b=t3.b
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a IS NULL);
a b a b
4 2 1 2
4 2 2 2
5 3 NULL NULL
ALTER TABLE t3
CHANGE COLUMN a a1 int,
CHANGE COLUMN c c1 int;
SELECT t2.a,t2.b,t3.a1,t3.b
FROM t2 LEFT JOIN t3 ON t2.b=t3.b
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a1 IS NULL);
a b a1 b
4 2 1 2
4 2 2 2
5 3 NULL NULL
SELECT t2.a,t2.b,t3.a1,t3.b
FROM t2 NATURAL LEFT JOIN t3
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a1 IS NULL);
a b a1 b
4 2 1 2
4 2 2 2
5 3 NULL NULL
DROP TABLE t0,t1,t2,t3,t4,t5,t6,t7,t8,t9;
mysql-test/r/join_outer.result
View file @ 356cbe4f
......@@ -356,13 +356,7 @@ select t1.name, t2.name, t2.id, t2.owner, t3.id from t1 left join t2 on (t1.id =
name name id owner id
Antonio Paz El Gato 1 1 1
Antonio Paz Perrito 2 1 1
Lilliana Angelovska NULL NULL NULL 1
Thimble Smith NULL NULL NULL 1
Antonio Paz NULL NULL NULL 2
Lilliana Angelovska NULL NULL NULL 2
Thimble Smith NULL NULL NULL 2
Antonio Paz NULL NULL NULL 3
Lilliana Angelovska NULL NULL NULL 3
NULL NULL NULL NULL 2
Thimble Smith Happy 3 3 3
drop table t1,t2;
create table t1 (id int not null, str char(10), index(str));
......
mysql-test/r/select.result
View file @ 356cbe4f
......@@ -2157,13 +2157,10 @@ a a a
3 3 3
select * from t1 inner join (t1 as t2 left join t1 as t3 using (a)) on t1.a>1;
a a a
1 1 NULL
2 1 1
3 1 1
1 2 NULL
2 2 2
3 2 2
1 3 NULL
2 3 3
3 3 3
select * from (t1 as t2 left join t1 as t3 using (a)) inner join t1 using ( a );
......@@ -2174,13 +2171,7 @@ a a a
select * from t1 inner join (t1 as t2 left join t1 as t3 using (a)) using ( a );
a a a
1 1 1
2 1 NULL
3 1 NULL
1 2 NULL
2 2 2
3 2 NULL
1 3 NULL
2 3 NULL
3 3 3
select * from (t1 as t2 left join t1 as t3 using (a)) left outer join t1 on t1.a>1;
a a a
......@@ -2192,14 +2183,12 @@ a a a
3 3 3
select * from t1 left outer join (t1 as t2 left join t1 as t3 using (a)) on t1.a>1;
a a a
1 1 NULL
1 NULL NULL
2 1 1
3 1 1
1 2 NULL
2 2 2
3 2 2
1 3 NULL
2 3 3
3 1 1
3 2 2
3 3 3
select * from (t1 as t2 left join t1 as t3 using (a)) left join t1 using ( a );
a a a
......@@ -2209,13 +2198,7 @@ a a a
select * from t1 left join (t1 as t2 left join t1 as t3 using (a)) using ( a );
a a a
1 1 1
2 1 NULL
3 1 NULL
1 2 NULL
2 2 2
3 2 NULL
1 3 NULL
2 3 NULL
3 3 3
select * from (t1 as t2 left join t1 as t3 using (a)) natural left join t1;
a a a
......@@ -2229,9 +2212,7 @@ a a a
3 3 3
select * from (t1 as t2 left join t1 as t3 using (a)) right join t1 on t1.a>1;
a a a
1 NULL 1
2 NULL 1
3 NULL 1
NULL NULL 1
1 1 2
2 2 2
3 3 2
......@@ -2249,13 +2230,7 @@ a a a
select * from (t1 as t2 left join t1 as t3 using (a)) right outer join t1 using ( a );
a a a
1 1 1
2 NULL 1
3 NULL 1
1 NULL 2
2 2 2
3 NULL 2
1 NULL 3
2 NULL 3
3 3 3
select * from t1 right outer join (t1 as t2 left join t1 as t3 using (a)) using ( a );
a a a
......@@ -2265,13 +2240,7 @@ a a a
select * from (t1 as t2 left join t1 as t3 using (a)) natural right join t1;
a a a
1 1 1
2 NULL 1
3 NULL 1
1 NULL 2
2 2 2
3 NULL 2
1 NULL 3
2 NULL 3
3 3 3
select * from t1 natural right join (t1 as t2 left join t1 as t3 using (a));
a a a
......
mysql-test/t/join_nested.test 0 → 100644
View file @ 356cbe4f
DROP TABLE IF EXISTS t0,t1,t2,t3,t4,t5,t6,t7,t8,t9;
CREATE TABLE t0 (a int, b int, c int);
CREATE TABLE t1 (a int, b int, c int);
CREATE TABLE t2 (a int, b int, c int);
CREATE TABLE t3 (a int, b int, c int);
CREATE TABLE t4 (a int, b int, c int);
CREATE TABLE t5 (a int, b int, c int);
CREATE TABLE t6 (a int, b int, c int);
CREATE TABLE t7 (a int, b int, c int);
CREATE TABLE t8 (a int, b int, c int);
CREATE TABLE t9 (a int, b int, c int);
INSERT INTO t0 VALUES (1,1,0), (1,2,0), (2,2,0);
INSERT INTO t1 VALUES (1,3,0), (2,2,0), (3,2,0);
INSERT INTO t2 VALUES (3,3,0), (4,2,0), (5,3,0);
INSERT INTO t3 VALUES (1,2,0), (2,2,0);
INSERT INTO t4 VALUES (3,2,0), (4,2,0);
INSERT INTO t5 VALUES (3,1,0), (2,2,0), (3,3,0);
INSERT INTO t6 VALUES (3,2,0), (6,2,0), (6,1,0);
INSERT INTO t7 VALUES (1,1,0), (2,2,0);
INSERT INTO t8 VALUES (0,2,0), (1,2,0);
INSERT INTO t9 VALUES (1,1,0), (1,2,0), (3,3,0);
SELECT t2.a,t2.b
FROM t2;
SELECT t3.a,t3.b
FROM t3;
SELECT t4.a,t4.b
FROM t4;
SELECT t3.a,t3.b,t4.a,t4.b
FROM t3,t4;
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t2.b=t4.b;
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b;
EXPLAIN
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t2.b=t4.b
WHERE t3.a=1 OR t3.c IS NULL;
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t2.b=t4.b
WHERE t3.a=1 OR t3.c IS NULL;
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t2.b=t4.b
WHERE t3.a>1 OR t3.c IS NULL;
SELECT t5.a,t5.b
FROM t5;
SELECT t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t3,t4,t5;
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t2
LEFT JOIN
(t3, t4, t5)
ON t2.b=t4.b;
EXPLAIN
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t2
LEFT JOIN
(t3, t4, t5)
ON t2.b=t4.b
WHERE t3.a>1 OR t3.c IS NULL;
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t2
LEFT JOIN
(t3, t4, t5)
ON t2.b=t4.b
WHERE t3.a>1 OR t3.c IS NULL;
EXPLAIN
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t2
LEFT JOIN
(t3, t4, t5)
ON t2.b=t4.b
WHERE (t3.a>1 OR t3.c IS NULL) AND
(t5.a<3 OR t5.c IS NULL);
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,t5.a,t5.b
FROM t2
LEFT JOIN
(t3, t4, t5)
ON t2.b=t4.b
WHERE (t3.a>1 OR t3.c IS NULL) AND
(t5.a<3 OR t5.c IS NULL);
SELECT t6.a,t6.b
FROM t6;
SELECT t7.a,t7.b
FROM t7;
SELECT t6.a,t6.b,t7.a,t7.b
FROM t6,t7;
SELECT t8.a,t8.b
FROM t8;
EXPLAIN
SELECT t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10;
SELECT t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10;
SELECT t5.a,t5.b
FROM t5;
SELECT t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b;
SELECT t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b AND
(t8.a < 1 OR t8.c IS NULL);
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b;
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b;
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
WHERE t2.a > 3 AND
(t6.a < 6 OR t6.c IS NULL);
SELECT t1.a,t1.b
FROM t1;
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2);
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2)
WHERE (t2.a >= 4 OR t2.c IS NULL);
SELECT t0.a,t0.b
FROM t0;
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2)
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL);
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2)
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL);
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
SELECT t9.a,t9.b
FROM t9;
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
SELECT t1.a,t1.b
FROM t1;
SELECT t2.a,t2.b
FROM t2;
SELECT t3.a,t3.b
FROM t3;
SELECT t2.a,t2.b,t3.a,t3.b
FROM t2
LEFT JOIN
t3
ON t2.b=t3.b;
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b
FROM t1, t2
LEFT JOIN
t3
ON t2.b=t3.b
WHERE t1.a <= 2;
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b
FROM t1, t3
RIGHT JOIN
t2
ON t2.b=t3.b
WHERE t1.a <= 2;
SELECT t3.a,t3.b,t4.a,t4.b
FROM t3,t4;
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b;
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t1, t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b
WHERE t1.a <= 2;
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t1, (t3, t4)
RIGHT JOIN
t2
ON t3.a=1 AND t2.b=t4.b
WHERE t1.a <= 2;
SELECT t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t1, t3, t4
RIGHT JOIN
t2
ON t3.a=1 AND t2.b=t4.b
WHERE t1.a <= 2;
CREATE INDEX idx_b ON t2(b);
EXPLAIN
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t3,t4
LEFT JOIN
(t1,t2)
ON t3.a=1 AND t3.b=t2.b AND t2.b=t4.b;
SELECT t2.a,t2.b,t3.a,t3.b,t4.a,t4.b
FROM t3,t4
LEFT JOIN
(t1,t2)
ON t3.a=1 AND t3.b=t2.b AND t2.b=t4.b;
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
CREATE INDEX idx_b ON t4(b);
CREATE INDEX idx_b ON t5(b);
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
CREATE INDEX idx_b ON t8(b);
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
CREATE INDEX idx_b ON t1(b);
CREATE INDEX idx_a ON t0(a);
EXPLAIN
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
SELECT t0.a,t0.b,t1.a,t1.b,t2.a,t2.b,t3.a,t3.b,t4.a,t4.b,
t5.a,t5.b,t6.a,t6.b,t7.a,t7.b,t8.a,t8.b,t9.a,t9.b
FROM t0,t1
LEFT JOIN
(
t2
LEFT JOIN
(t3, t4)
ON t3.a=1 AND t2.b=t4.b,
t5
LEFT JOIN
(
t6,
t7
LEFT JOIN
t8
ON t7.b=t8.b AND t6.b < 10
)
ON t6.b >= 2 AND t5.b=t7.b
)
ON (t3.b=2 OR t3.c IS NULL) AND (t6.b=2 OR t6.c IS NULL) AND
(t1.b=t5.b OR t3.c IS NULL OR t6.c IS NULL or t8.c IS NULL) AND
(t1.a != 2),
t9
WHERE t0.a=1 AND
t0.b=t1.b AND
(t2.a >= 4 OR t2.c IS NULL) AND
(t3.a < 5 OR t3.c IS NULL) AND
(t3.b=t4.b OR t3.c IS NULL OR t4.c IS NULL) AND
(t5.a >=2 OR t5.c IS NULL) AND
(t6.a >=4 OR t6.c IS NULL) AND
(t7.a <= 2 OR t7.c IS NULL) AND
(t8.a < 1 OR t8.c IS NULL) AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
SELECT t2.a,t2.b
FROM t2;
SELECT t3.a,t3.b
FROM t3;
SELECT t2.a,t2.b,t3.a,t3.b
FROM t2 LEFT JOIN t3 ON t2.b=t3.b
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a IS NULL);
SELECT t2.a,t2.b,t3.a,t3.b
FROM t2 LEFT JOIN (t3) ON t2.b=t3.b
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a IS NULL);
ALTER TABLE t3
CHANGE COLUMN a a1 int,
CHANGE COLUMN c c1 int;
SELECT t2.a,t2.b,t3.a1,t3.b
FROM t2 LEFT JOIN t3 ON t2.b=t3.b
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a1 IS NULL);
SELECT t2.a,t2.b,t3.a1,t3.b
FROM t2 NATURAL LEFT JOIN t3
WHERE t2.a = 4 OR (t2.a > 4 AND t3.a1 IS NULL);
DROP TABLE t0,t1,t2,t3,t4,t5,t6,t7,t8,t9;
sql/item_cmpfunc.h
View file @ 356cbe4f
......@@ -214,6 +214,40 @@ public:
Item *neg_transformer();
};
/*
The class Item_func_trig_cond is used for guarded predicates
which are employed only for internal purposes.
A guarded predicates is an object consisting of an a regular or
a guarded predicate P and a pointer to a boolean guard variable g.
A guarded predicate P/g is evaluated to true if the value of the
guard g is false, otherwise it is evaluated to the same value that
the predicate P: val(P/g)= g ? val(P):true.
Guarded predicates allow us to include predicates into a conjunction
conditionally. Currently they are utilized for pushed down predicates
in queries with outer join operations.
In the future, probably, it makes sense to extend this class to
the objects consisting of three elements: a predicate P, a pointer
to a variable g and a firing value s with following evaluation
rule: val(P/g,s)= g==s? val(P) : true. It will allow us to build only
one item for the objects of the form P/g1/g2...
Objects of this class are built only for query execution after
the execution plan has been already selected. That's why this
class needs only val_int out of generic methods.
*/
class Item_func_trig_cond: public Item_bool_func
{
bool *trig_var;
public:
Item_func_trig_cond(Item *a, bool *f) : Item_bool_func(a) { trig_var= f; }
longlong val_int() { return *trig_var ? args[0]->val_int() : 1; }
enum Functype functype() const { return TRIG_COND_FUNC; };
const char *func_name() const { return "trigcond"; };
};
class Item_func_not_all :public Item_func_not
{
bool abort_on_null;
......@@ -793,7 +827,7 @@ public:
}
const char *func_name() const { return "isnotnull"; }
optimize_type select_optimize() const { return OPTIMIZE_NULL; }
table_map not_null_tables() const { return 0; }
table_map not_null_tables() const { return used_tables(); }
Item *neg_transformer();
void print(String *str);
};
......
sql/item_func.h
View file @ 356cbe4f
......@@ -47,7 +47,7 @@ public:
SP_CONTAINS_FUNC,SP_OVERLAPS_FUNC,
SP_STARTPOINT,SP_ENDPOINT,SP_EXTERIORRING,
SP_POINTN,SP_GEOMETRYN,SP_INTERIORRINGN,
NOT_FUNC, NOT_ALL_FUNC,
NOT_FUNC, NOT_ALL_FUNC, TRIG_COND_FUNC,
GUSERVAR_FUNC};
enum optimize_type { OPTIMIZE_NONE,OPTIMIZE_KEY,OPTIMIZE_OP, OPTIMIZE_NULL };
enum Type type() const { return FUNC_ITEM; }
......
sql/sql_base.cc
View file @ 356cbe4f
......@@ -2204,40 +2204,64 @@ int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds)
thd->where="where clause";
if ((*conds)->fix_fields(thd, tables, conds) || (*conds)->check_cols(1))
DBUG_RETURN(1);
not_null_tables= (*conds)->not_null_tables();
}
/* Check if we are using outer joins */
for (TABLE_LIST *table=tables ; table ; table=table->next)
{
if (table->on_expr)
TABLE_LIST *embedded;
TABLE_LIST *embedding= table;
do
{
embedded= embedding;
if (embedded->on_expr)
{
/* Make a join an a expression */
thd->where="on clause";
if (table->on_expr->fix_fields(thd, tables, &table->on_expr) ||
table->on_expr->check_cols(1))
if (embedded->on_expr->fix_fields(thd, tables, &embedded->on_expr) ||
embedded->on_expr->check_cols(1))
DBUG_RETURN(1);
thd->lex->current_select->cond_count++;
/*
If it's a normal join or a LEFT JOIN which can be optimized away
add the ON/USING expression to the WHERE
*/
if (!table->outer_join ||
((table->table->map & not_null_tables) &&
!(specialflag & SPECIAL_NO_NEW_FUNC)))
}
if (embedded->natural_join)
{
table->outer_join= 0;
if (!(*conds=and_conds(*conds, table->on_expr)))
DBUG_RETURN(1);
table->on_expr=0;
/* Make a join of all fields with have the same name */
TABLE_LIST *tab1= embedded;
TABLE_LIST *tab2= embedded->natural_join;
if (!(embedded->outer_join & JOIN_TYPE_RIGHT))
{
while (tab1->nested_join)
{
TABLE_LIST *next;
List_iterator_fast<TABLE_LIST> it(tab1->nested_join->join_list);
tab1= it++;
while ((next= it++))
tab1= next;
}
}
if (table->natural_join)
else
{
/* Make a join of all fields with have the same name */
TABLE *t1=table->table;
TABLE *t2=table->natural_join->table;
while (tab1->nested_join)
tab1= tab1->nested_join->join_list.head();
}
if (embedded->outer_join & JOIN_TYPE_RIGHT)
{
while (tab2->nested_join)
{
TABLE_LIST *next;
List_iterator_fast<TABLE_LIST> it(tab2->nested_join->join_list);
tab2= it++;
while ((next= it++))
tab2= next;
}
}
else
{
while (tab2->nested_join)
tab2= tab2->nested_join->join_list.head();
}
TABLE *t1=tab1->table;
TABLE *t2=tab2->table;
Item_cond_and *cond_and=new Item_cond_and();
if (!cond_and) // If not out of memory
DBUG_RETURN(1);
......@@ -2270,14 +2294,20 @@ int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds)
}
cond_and->used_tables_cache= t1->map | t2->map;
thd->lex->current_select->cond_count+= cond_and->list.elements;
if (!table->outer_join) // Not left join
COND *on_expr= cond_and;
on_expr->fix_fields(thd, 0, &on_expr);
if (!embedded->outer_join) // Not left join
{
if (!(*conds=and_conds(*conds, cond_and)))
if (!(*conds=and_conds(*conds, on_expr)))
DBUG_RETURN(1);
}
else
table->on_expr=and_conds(table->on_expr,cond_and);
embedded->on_expr=and_conds(embedded->on_expr,on_expr);
}
embedding= embedded->embedding;
}
while (embedding &&
embedding->nested_join->join_list.head() == embedded);
}
DBUG_RETURN(test(thd->net.report_error));
}
......
sql/sql_lex.cc
View file @ 356cbe4f
......@@ -1014,6 +1014,9 @@ void st_select_lex::init_query()
{
st_select_lex_node::init_query();
table_list.empty();
top_join_list.empty();
join_list= &top_join_list;
embedding= 0;
item_list.empty();
join= 0;
where= 0;
......
sql/sql_lex.h
View file @ 356cbe4f
......@@ -400,6 +400,9 @@ public:
List<Item_func_match> *ftfunc_list;
List<Item_func_match> ftfunc_list_alloc;
JOIN *join; /* after JOIN::prepare it is pointer to corresponding JOIN */
List<TABLE_LIST> top_join_list; /* join list of the top level */
List<TABLE_LIST> *join_list; /* list for the currently parsed join */
TABLE_LIST *embedding; /* table embedding to the above list */
const char *type; /* type of select for EXPLAIN */
SQL_LIST order_list; /* ORDER clause */
......@@ -488,6 +491,12 @@ public:
List<String> *ignore_index= 0,
LEX_STRING *option= 0);
TABLE_LIST* get_table_list();
bool init_nested_join(THD *thd);
TABLE_LIST *end_nested_join(THD *thd);
TABLE_LIST *nest_last_join(THD *thd);
void save_names_for_using_list(TABLE_LIST *tab1, TABLE_LIST *tab2);
void add_joined_table(TABLE_LIST *table);
TABLE_LIST *convert_right_join();
List<Item>* get_item_list();
List<String>* get_use_index();
List<String>* get_ignore_index();
......
sql/sql_parse.cc
View file @ 356cbe4f
......@@ -4686,6 +4686,238 @@ TABLE_LIST *st_select_lex::add_table_to_list(THD *thd,
}
/*
Initialize a new table list for a nested join
SYNOPSIS
init_table_list()
thd current thread
DESCRIPTION
The function initializes a structure of the TABLE_LIST type
for a nested join. It sets up its nested join list as empty.
The created structure is added to the front of the current
join list in the st_select_lex object. Then the function
changes the current nest level for joins to refer to the newly
created empty list after having saved the info on the old level
in the initialized structure.
RETURN VALUE
0, if success
1, otherwise
*/
bool st_select_lex::init_nested_join(THD *thd)
{
TABLE_LIST *ptr;
NESTED_JOIN *nested_join;
DBUG_ENTER("init_nested_join");
if (!(ptr = (TABLE_LIST *) thd->calloc(sizeof(TABLE_LIST))) ||
!(nested_join= ptr->nested_join=
(NESTED_JOIN *) thd->calloc(sizeof(NESTED_JOIN))))
DBUG_RETURN(1);
join_list->push_front(ptr);
ptr->embedding= embedding;
ptr->join_list= join_list;
embedding= ptr;
join_list= &nested_join->join_list;
join_list->empty();
nested_join->used_tables= nested_join->not_null_tables= (table_map) 0;
DBUG_RETURN(0);
}
/*
End a nested join table list
SYNOPSIS
end_nested_join()
thd current thread
DESCRIPTION
The function returns to the previous join nest level.
If the current level contains only one member, the function
moves it one level up, eliminating the nest.
RETURN VALUE
Pointer to TABLE_LIST element added to the total table list, if success
0, otherwise
*/
TABLE_LIST *st_select_lex::end_nested_join(THD *thd)
{
TABLE_LIST *ptr;
DBUG_ENTER("end_nested_join");
ptr= embedding;
join_list= ptr->join_list;
embedding= ptr->embedding;
NESTED_JOIN *nested_join= ptr->nested_join;
if (nested_join->join_list.elements == 1)
{
TABLE_LIST *embedded= nested_join->join_list.head();
join_list->pop();
embedded->join_list= join_list;
embedded->embedding= embedding;
join_list->push_front(embedded);
ptr= embedded;
}
DBUG_RETURN(ptr);
}
/*
Nest last join operation
SYNOPSIS
nest_last_join()
thd current thread
DESCRIPTION
The function nest last join operation as if it was enclosed in braces.
RETURN VALUE
Pointer to TABLE_LIST element created for the new nested join, if success
0, otherwise
*/
TABLE_LIST *st_select_lex::nest_last_join(THD *thd)
{
TABLE_LIST *ptr;
NESTED_JOIN *nested_join;
DBUG_ENTER("nest_last_join");
if (!(ptr = (TABLE_LIST *) thd->calloc(sizeof(TABLE_LIST))) ||
!(nested_join= ptr->nested_join=
(NESTED_JOIN *) thd->calloc(sizeof(NESTED_JOIN))))
DBUG_RETURN(0);
ptr->embedding= embedding;
ptr->join_list= join_list;
List<TABLE_LIST> *embedded_list= &nested_join->join_list;
embedded_list->empty();
for (int i=0; i < 2; i++)
{
TABLE_LIST *table= join_list->pop();
table->join_list= embedded_list;
table->embedding= ptr;
embedded_list->push_back(table);
}
join_list->push_front(ptr);
nested_join->used_tables= nested_join->not_null_tables= (table_map) 0;
DBUG_RETURN(ptr);
}
/*
Save names for a join with using clase
SYNOPSIS
save_names_for_using_list
tab1 left table in join
tab2 right table in join
DESCRIPTION
The function saves the full names of the tables in st_select_lex
to be able to build later an on expression to replace the using clause.
RETURN VALUE
None
*/
void st_select_lex::save_names_for_using_list(TABLE_LIST *tab1,
TABLE_LIST *tab2)
{
while (tab1->nested_join)
{
tab1= tab1->nested_join->join_list.head();
}
db1= tab1->db;
table1= tab1->alias;
while (tab2->nested_join)
{
TABLE_LIST *next;
List_iterator_fast<TABLE_LIST> it(tab2->nested_join->join_list);
tab2= it++;
while ((next= it++))
tab2= next;
}
db2= tab2->db;
table2= tab2->alias;
}
/*
Add a table to the current join list
SYNOPSIS
add_joined_table()
table the table to add
DESCRIPTION
The function puts a table in front of the current join list
of st_select_lex object.
Thus, joined tables are put into this list in the reverse order
(the most outer join operation follows first).
RETURN VALUE
None
*/
void st_select_lex::add_joined_table(TABLE_LIST *table)
{
DBUG_ENTER("add_joined_table");
join_list->push_front(table);
table->join_list= join_list;
table->embedding= embedding;
DBUG_VOID_RETURN;
}
/*
Convert a right join into equivalent left join
SYNOPSIS
convert_right_join()
thd current thread
DESCRIPTION
The function takes the current join list t[0],t[1] ... and
effectively converts it into the list t[1],t[0] ...
Although the outer_join flag for the new nested table contains
JOIN_TYPE_RIGHT, it will be handled as the inner table of a left join
operation.
EXAMPLES
SELECT * FROM t1 RIGHT JOIN t2 ON on_expr =>
SELECT * FROM t2 LEFT JOIN t1 ON on_expr
SELECT * FROM t1,t2 RIGHT JOIN t3 ON on_expr =>
SELECT * FROM t1,t3 LEFT JOIN t2 ON on_expr
SELECT * FROM t1,t2 RIGHT JOIN (t3,t4) ON on_expr =>
SELECT * FROM t1,(t3,t4) LEFT JOIN t2 ON on_expr
SELECT * FROM t1 LEFT JOIN t2 ON on_expr1 RIGHT JOIN t3 ON on_expr2 =>
SELECT * FROM t3 LEFT JOIN (t1 LEFT JOIN t2 ON on_expr2) ON on_expr1
RETURN
Pointer to the table representing the inner table, if success
0, otherwise
*/
TABLE_LIST *st_select_lex::convert_right_join()
{
TABLE_LIST *tab2= join_list->pop();
TABLE_LIST *tab1= join_list->pop();
DBUG_ENTER("convert_right_join");
join_list->push_front(tab2);
join_list->push_front(tab1);
tab1->outer_join|= JOIN_TYPE_RIGHT;
DBUG_RETURN(tab1);
}
/*
Set lock for all tables in current select level
......
sql/sql_select.cc
View file @ 356cbe4f
......@@ -61,6 +61,7 @@ static store_key *get_store_key(THD *thd,
KEY_PART_INFO *key_part, char *key_buff,
uint maybe_null);
static bool make_simple_join(JOIN *join,TABLE *tmp_table);
static void make_outerjoin_info(JOIN *join);
static bool make_join_select(JOIN *join,SQL_SELECT *select,COND *item);
static void make_join_readinfo(JOIN *join,uint options);
static bool only_eq_ref_tables(JOIN *join, ORDER *order, table_map tables);
......@@ -73,7 +74,10 @@ static int return_zero_rows(JOIN *join, select_result *res,TABLE_LIST *tables,
uint select_options, const char *info,
Item *having, Procedure *proc,
SELECT_LEX_UNIT *unit);
static COND *simplify_joins(JOIN *join, List<TABLE_LIST> *join_list,
COND *conds, bool top);
static COND *optimize_cond(COND *conds,Item::cond_result *cond_value);
static bool resolve_nested_join (TABLE_LIST *table);
static COND *remove_eq_conds(COND *cond,Item::cond_result *cond_value);
static bool const_expression_in_where(COND *conds,Item *item, Item **comp_item);
static bool open_tmp_table(TABLE *table);
......@@ -128,6 +132,7 @@ static int remove_dup_with_compare(THD *thd, TABLE *entry, Field **field,
ulong offset,Item *having);
static int remove_dup_with_hash_index(THD *thd, TABLE *table,
uint field_count, Field **first_field,
ulong key_length,Item *having);
static int join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count);
static ulong used_blob_length(CACHE_FIELD **ptr);
......@@ -299,6 +304,7 @@ JOIN::prepare(Item ***rref_pointer_array,
tables_list= tables_init;
select_lex= select_lex_arg;
select_lex->join= this;
join_list= &select_lex->top_join_list;
union_part= (unit_arg->first_select()->next_select() != 0);
/* Check that all tables, fields, conds and order are ok */
......@@ -486,7 +492,6 @@ bool JOIN::test_in_subselect(Item **where)
return 0;
}
/*
global select optimisation.
return 0 - success
......@@ -524,6 +529,9 @@ JOIN::optimize()
}
#endif
/* Convert all outer joins to inner joins if possible */
conds= simplify_joins(this, join_list, conds, TRUE);
conds= optimize_cond(conds,&cond_value);
if (thd->net.report_error)
{
......@@ -637,6 +645,9 @@ JOIN::optimize()
DBUG_PRINT("error",("Error: make_select() failed"));
DBUG_RETURN(1);
}
make_outerjoin_info(this);
if (make_join_select(this, select, conds))
{
zero_result_cause=
......@@ -1456,7 +1467,7 @@ JOIN::exec()
at least one row generated from the table.
*/
if (curr_table->select_cond ||
(curr_table->keyuse && !curr_table->on_expr))
(curr_table->keyuse && !curr_table->first_inner))
{
/* We have to sort all rows */
curr_join->select_limit= HA_POS_ERROR;
......@@ -1676,6 +1687,7 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
DYNAMIC_ARRAY *keyuse_array)
{
int error;
TABLE *table;
uint i,table_count,const_count,key;
table_map found_const_table_map, all_table_map, found_ref, refs;
key_map const_ref, eq_part;
......@@ -1701,13 +1713,15 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
for (s=stat,i=0 ; tables ; s++,tables=tables->next,i++)
{
TABLE *table;
table_map dep_tables;
TABLE_LIST *embedding= tables->embedding;
stat_vector[i]=s;
s->keys.init();
s->const_keys.init();
s->checked_keys.init();
s->needed_reg.init();
table_vector[i]=s->table=table=tables->table;
table->pos_in_table_list= tables;
table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);// record count
table->quick_keys.clear_all();
table->reginfo.join_tab=s;
......@@ -1716,29 +1730,36 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
all_table_map|= table->map;
s->join=join;
s->info=0; // For describe
s->dependent= tables->dep_tables;
s->key_dependent= 0;
if ((s->on_expr=tables->on_expr))
{
/* Left join */
/* s is the only inner table of an outer join */
if (!table->file->records)
{ // Empty table
s->key_dependent=s->dependent=0; // Ignore LEFT JOIN depend.
s->dependent= 0; // Ignore LEFT JOIN depend.
set_position(join,const_count++,s,(KEYUSE*) 0);
continue;
}
s->key_dependent=s->dependent=
s->on_expr->used_tables() & ~(table->map);
if (table->outer_join & JOIN_TYPE_LEFT)
s->dependent|=stat_vector[i-1]->dependent | table_vector[i-1]->map;
if (tables->outer_join & JOIN_TYPE_RIGHT)
s->dependent|=tables->next->table->map;
outer_join|=table->map;
outer_join|= table->map;
continue;
}
if (tables->straight) // We don't have to move this
s->dependent= table_vector[i-1]->map | stat_vector[i-1]->dependent;
else
s->dependent=(table_map) 0;
s->key_dependent=(table_map) 0;
if (embedding)
{
/* s belongs to a nested join, maybe to several embedded joins */
do
{
NESTED_JOIN *nested_join= embedding->nested_join;
s->dependent|= embedding->dep_tables;
embedding= embedding->embedding;
outer_join|= nested_join->used_tables;
}
while (embedding);
continue;
}
if ((table->system || table->file->records <= 1) && ! s->dependent &&
!(table->file->table_flags() & HA_NOT_EXACT_COUNT) &&
!table->fulltext_searched)
......@@ -1749,39 +1770,35 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
stat_vector[i]=0;
join->outer_join=outer_join;
if (join->outer_join)
{
/*
If outer join: Re-arrange tables in stat_vector so that outer join
tables are after all tables it is dependent of.
For example: SELECT * from A LEFT JOIN B ON B.c=C.c, C WHERE A.C=C.C
Will shift table B after table C.
Build transitive closure for relation 'to be dependent on'.
This will speed up the plan search for many cases with outer joins,
as well as allow us to catch illegal cross references/
Warshall's algorithm is used to build the transitive closure.
As we use bitmaps to represent the relation the complexity
of the algorithm is O(number of tables).
*/
if (outer_join)
for (i= 0, s= stat ; i < table_count ; i++, s++)
{
table_map used_tables=0L;
for (i=0 ; i < join->tables-1 ; i++)
for (uint j= 0 ; j < table_count ; j++)
{
if (stat_vector[i]->dependent & ~used_tables)
{
JOIN_TAB *save= stat_vector[i];
uint j;
for (j=i+1;
j < join->tables && stat_vector[j]->dependent & ~used_tables;
j++)
{
JOIN_TAB *tmp=stat_vector[j]; // Move element up
stat_vector[j]=save;
save=tmp;
table= stat[j].table;
if (s->dependent & table->map)
s->dependent |= table->reginfo.join_tab->dependent;
}
if (j == join->tables)
}
/* Catch illegal cross references for outer joins */
for (i= 0, s= stat ; i < table_count ; i++, s++)
{
if (s->dependent & s->table->map)
{
join->tables=0; // Don't use join->table
my_error(ER_WRONG_OUTER_JOIN,MYF(0));
DBUG_RETURN(1);
}
stat_vector[i]=stat_vector[j];
stat_vector[j]=save;
}
used_tables|= stat_vector[i]->table->map;
s->key_dependent= s->dependent;
}
}
......@@ -1824,7 +1841,7 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
for (JOIN_TAB **pos=stat_vector+const_count ; (s= *pos) ; pos++)
{
TABLE *table=s->table;
table=s->table;
if (s->dependent) // If dependent on some table
{
// All dep. must be constants
......@@ -2481,11 +2498,32 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
}
for (i=0 ; i < tables ; i++)
{
/*
Block the creation of keys for inner tables of outer joins.
Here only the outer joins that can not be converted to
inner joins are left and all nests that can be eliminated
are flattened.
In the future when we introduce conditional accesses
for inner tables in outer joins these keys will be taken
into account as well.
*/
if (join_tab[i].on_expr)
{
add_key_fields(join_tab,&end,&and_level,join_tab[i].on_expr,
join_tab[i].table->map);
}
else
{
TABLE_LIST *tab= join_tab[i].table->pos_in_table_list;
TABLE_LIST *embedding= tab->embedding;
if (embedding)
{
NESTED_JOIN *nested_join= embedding->nested_join;
if (nested_join->join_list.head() == tab)
add_key_fields(join_tab, &end, &and_level, embedding->on_expr,
nested_join->used_tables);
}
}
}
/* fill keyuse with found key parts */
for ( ; field != end ; field++)
......@@ -2923,7 +2961,7 @@ find_best(JOIN *join,table_map rest_tables,uint idx,double record_count,
{
/* Estimate cost of reading table. */
tmp= s->table->file->scan_time();
if (s->on_expr) // Can't use join cache
if (s->table->map & join->outer_join) // Can't use join cache
{
/*
For each record we have to:
......@@ -3357,6 +3395,8 @@ make_simple_join(JOIN *join,TABLE *tmp_table)
join_tab->keys.init(~0); /* test everything in quick */
join_tab->info=0;
join_tab->on_expr=0;
join_tab->last_inner= 0;
join_tab->first_unmatched= 0;
join_tab->ref.key = -1;
join_tab->not_used_in_distinct=0;
join_tab->read_first_record= join_init_read_record;
......@@ -3368,6 +3408,134 @@ make_simple_join(JOIN *join,TABLE *tmp_table)
}
/*
Build a predicate guarded by match variables for embedding outer joins
SYNOPSIS
add_found_match_trig_cond()
tab the first inner table for most nested outer join
cond the predicate to be guarded
root_tab the first inner table to stop
DESCRIPTION
The function recursively adds guards for predicate cond
assending from tab to the first inner table next embedding
nested outer join and so on until it reaches root_tab
(root_tab can be 0).
RETURN VALUE
pointer to the guarded predicate, if success
0, otherwise
*/
static COND*
add_found_match_trig_cond(JOIN_TAB *tab, COND *cond, JOIN_TAB *root_tab)
{
COND *tmp;
if (tab == root_tab || !cond)
return cond;
if ((tmp= add_found_match_trig_cond(tab->first_upper, cond, root_tab)))
{
tmp= new Item_func_trig_cond(tmp, &tab->found);
}
return tmp;
}
/*
Fill in outer join related info for the execution plan structure
SYNOPSIS
make_outerjoin_info()
join - reference to the info fully describing the query
DESCRIPTION
For each outer join operation left after simplification of the
original query the function set up the following pointers in the linear
structure join->join_tab representing the selected execution plan.
The first inner table t0 for the operation is set to refer to the last
inner table tk through the field t0->last_inner.
Any inner table ti for the operation are set to refer to the first
inner table ti->first_inner.
The first inner table t0 for the operation is set to refer to the
first inner table of the embedding outer join operation, if there is any,
through the field t0->first_upper.
The on expression for the outer join operation is attached to the
corresponding first inner table through the field t0->on_expr.
Here ti are structures of the JOIN_TAB type.
EXAMPLE
For rhe query:
SELECT * FROM t1
LEFT JOIN
(t2, t3 LEFT JOIN t4 ON t3.a=t4.a)
ON (t1.a=t2.a AND t1.b=t3.b)
WHERE t1.c > 5,
given the execution plan with the table order t1,t2,t3,t4
is selected, the following references will be set;
t4->last_inner=[t4], t4->first_inner=[t4], t4->first_upper=[t2]
t2->last_inner=[t4], t2->first_inner=t3->first_inner=[t2],
on expression (t1.a=t2.a AND t1.b=t3.b) will be attached to t2->on_expr,
while t3.a=t4.a will be attached to t4->on_expr.
NOTES
The function assumes that the simplification procedure has been
already applied to the join query (see simplify_joins).
This function can be called only after the execution plan
has been chosen.
RETURN VALUE
None.
*/
static void
make_outerjoin_info(JOIN *join)
{
for (uint i=join->const_tables ; i < join->tables ; i++)
{
JOIN_TAB *tab=join->join_tab+i;
TABLE *table=tab->table;
TABLE_LIST *tbl= table->pos_in_table_list;
TABLE_LIST *embedding= tbl->embedding;
if (tbl->outer_join)
{
/*
Table tab is the only one inner table for outer join.
(Like table t4 for the table reference t3 LEFT JOIN t4 ON t3.a=t4.a
is in the query above.)
*/
tab->last_inner= tab->first_inner= tab;
tab->on_expr= tbl->on_expr;
if (embedding)
tab->first_upper= embedding->nested_join->first_nested;
}
while (embedding)
{
NESTED_JOIN *nested_join= embedding->nested_join;
if (!nested_join->counter)
{
/*
Table tab is the first inner table for nested_join.
Save reference to it in the nested join structure.
*/
nested_join->first_nested= tab;
tab->on_expr= embedding->on_expr;
if (embedding->embedding)
tab->first_upper= embedding->embedding->nested_join->first_nested;
}
if (!tab->first_inner)
tab->first_inner= nested_join->first_nested;
if (++nested_join->counter < nested_join->join_list.elements)
break;
/* Table tab is the last inner table for nested join. */
nested_join->first_nested->last_inner= tab;
embedding= embedding->embedding;
}
}
}
static bool
make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
{
......@@ -3394,6 +3562,7 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
for (uint i=join->const_tables ; i < join->tables ; i++)
{
JOIN_TAB *tab=join->join_tab+i;
JOIN_TAB *first_inner_tab= tab->first_inner;
table_map current_map= tab->table->map;
/*
Following force including random expression in last table condition.
......@@ -3432,7 +3601,16 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
join->thd->memdup((gptr) select, sizeof(SQL_SELECT));
if (!sel)
DBUG_RETURN(1); // End of memory
/*
If tab is an inner table of an outer join operation,
add a match guard to the pushed down predicate.
The guard will turn the predicate on only after
the first match for outer tables is encountered.
*/
if (!(tmp= add_found_match_trig_cond(first_inner_tab, tmp, 0)))
DBUG_RETURN(1);
tab->select_cond=sel->cond=tmp;
sel->head=tab->table;
if (tab->quick)
{
......@@ -3541,12 +3719,61 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
}
}
}
/*
Push down all predicates from on expressions.
Each of these predicated are guarded by a variable
that turns if off just before null complemented row for
outer joins is formed. Thus, the predicates from an
'on expression' are guaranteed not to be checked for
the null complemented row.
*/
JOIN_TAB *last_tab= tab;
while (first_inner_tab && first_inner_tab->last_inner == last_tab)
{
/*
Table tab is the last inner table of an outer join.
An on expression is always attached to it.
*/
COND *on_expr= first_inner_tab->on_expr;
table_map used_tables= join->const_table_map |
OUTER_REF_TABLE_BIT | RAND_TABLE_BIT;
for (tab= join->join_tab+join->const_tables; tab <= last_tab ; tab++)
{
current_map= tab->table->map;
used_tables|= current_map;
COND *tmp= make_cond_for_table(on_expr, used_tables, current_map);
if (tmp)
{
JOIN_TAB *cond_tab= tab < first_inner_tab ? first_inner_tab : tab;
/*
First add the guards for match variables of
all embedding outer join operations.
*/
if (!(tmp= add_found_match_trig_cond(cond_tab->first_inner,
tmp, first_inner_tab)))
DBUG_RETURN(1);
/*
Now add the guard turning the predicate off for
the null complemented row.
*/
tmp= new Item_func_trig_cond(tmp,
&first_inner_tab->not_null_compl);
/* Add the predicate to other pushed down predicates */
cond_tab->select_cond= !cond_tab->select_cond ? tmp :
new Item_cond_and(cond_tab->select_cond,tmp);
if (!cond_tab->select_cond)
DBUG_RETURN(1);
}
}
first_inner_tab= first_inner_tab->first_upper;
}
}
}
DBUG_RETURN(0);
}
static void
make_join_readinfo(JOIN *join, uint options)
{
......@@ -3631,7 +3858,7 @@ make_join_readinfo(JOIN *join, uint options)
*/
table->status=STATUS_NO_RECORD;
if (i != join->const_tables && !(options & SELECT_NO_JOIN_CACHE) &&
tab->use_quick != 2 && !tab->on_expr)
tab->use_quick != 2 && !tab->first_inner)
{
if ((options & SELECT_DESCRIBE) ||
!join_init_cache(join->thd,join->join_tab+join->const_tables,
......@@ -4334,6 +4561,231 @@ COND *eliminate_not_funcs(COND *cond)
}
/*
Simplify joins replacing outer joins by inner joins whenever it's possible
SYNOPSIS
simplify_joins()
join reference to the query info
join_list list representation of the join to be converted
conds conditions to add on expressions for converted joins
top true <=> conds is the where condition
DESCRIPTION
The function, during a retrieval of join_list, eliminates those
outer joins that can be converted into inner join, possibly nested.
It also moves the on expressions for the converted outer joins
and from inner joins to conds.
The function also calculates some attributes for nested joins:
- used_tables
- not_null_tables
- dep_tables.
- on_expr_dep_tables
The first two attributes are used to test whether an outer join can
be substituted for an inner join. The third attribute represents the
relation 'to be dependent on' for tables. If table t2 is dependent
on table t1, then in any evaluated execution plan table access to
table t2 must precede access to table t2. This relation is used also
to check whether the query contains invalid cross-references.
The forth attribute is an auxiliary one and is used to calculate
dep_tables.
As the attribute dep_tables qualifies possibles orders of tables in the
execution plan, the dependencies required by the straight join
modifiers are reflected in this attribute as well.
The function also removes all braces that can be removed from the join
expression without changing its meaning.
NOTES
An outer join can be replaced by an inner join if the where condition
or the on expression for an embedding nested join contains a conjunctive
predicate rejecting null values for some attribute of the inner tables.
E.g. in the query:
SELECT * FROM t1 LEFT JOIN t2 ON t2.a=t1.a WHERE t2.b < 5
the predicate t2.b < 5 rejects nulls.
The query is converted first to:
SELECT * FROM t1 INNER JOIN t2 ON t2.a=t1.a WHERE t2.b < 5
then to the equivalent form:
SELECT * FROM t1, t2 ON t2.a=t1.a WHERE t2.b < 5 AND t2.a=t1.a.
Similarly the following query:
SELECT * from t1 LEFT JOIN (t2, t3) ON t2.a=t1.a t3.b=t1.b
WHERE t2.c < 5
is converted to:
SELECT * FROM t1, (t2, t3) WHERE t2.c < 5 AND t2.a=t1.a t3.b=t1.b
One conversion might trigger another:
SELECT * FROM t1 LEFT JOIN t2 ON t2.a=t1.a
LEFT JOIN t3 ON t3.b=t2.b
WHERE t3 IS NOT NULL =>
SELECT * FROM t1 LEFT JOIN t2 ON t2.a=t1.a, t3
WHERE t3 IS NOT NULL AND t3.b=t2.b =>
SELECT * FROM t1, t2, t3
WHERE t3 IS NOT NULL AND t3.b=t2.b AND t2.a=t1.a
The function removes all unnecessary braces from the expression
produced by the conversions.
E.g. SELECT * FROM t1, (t2, t3) WHERE t2.c < 5 AND t2.a=t1.a t3.b=t1.b
finally is converted to:
SELECT * FROM t1, t2, t3 WHERE t2.c < 5 AND t2.a=t1.a t3.b=t1.b
It also will remove braces from the following queries:
SELECT * from (t1 LEFT JOIN t2 ON t2.a=t1.a) LEFT JOIN t3 ON t3.b=t2.b
SELECT * from (t1, (t2,t3)) WHERE t1.a=t2.a AND t2.b=t3.b.
The benefit of this simplification procedure is that it might return
a query for which the optimizer can evaluate execution plan with more
join orders. With a left join operation the optimizer does not
consider any plan where one of the inner tables is before some of outer
tables.
IMPLEMENTATION.
The function is implemented by a recursive procedure. On the recursive
ascent all attributes are calculated, all outer joins that can be
converted are replaced and then all unnecessary braces are removed.
As join list contains join tables in the reverse order sequential
elimination of outer joins does not requite extra recursive calls.
EXAMPLES
Here is an example of a join query with invalid cross references:
SELECT * FROM t1 LEFT JOIN t2 ON t2.a=t3.a LEFT JOIN ON t3.b=t1.b
RETURN VALUE
The new condition, if success
0, otherwise
*/
static COND *
simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top)
{
TABLE_LIST *table;
NESTED_JOIN *nested_join;
TABLE_LIST *prev_table= 0;
List_iterator<TABLE_LIST> li(*join_list);
/*
Try to simplify join operations from join_list.
The most outer join operation is checked for conversion first.
*/
while ((table= li++))
{
table_map used_tables;
table_map not_null_tables= (table_map) 0;
if ((nested_join= table->nested_join))
{
/*
If the element of join_list is a nested join apply
the procedure to its nested join list first.
*/
if (table->on_expr)
{
/*
If an on expression E is attached to the table,
check all null rejected predicates in this expression.
If such a predicate over an attribute belonging to
an inner table of an embedded outer join is found,
the outer join is converted to an inner join and
the corresponding on expression is added to E.
*/
table->on_expr= simplify_joins(join, &nested_join->join_list,
table->on_expr, top && FALSE);
}
nested_join->used_tables= (table_map) 0;
nested_join->not_null_tables=(table_map) 0;
conds= simplify_joins(join, &nested_join->join_list, conds, top);
used_tables= nested_join->used_tables;
not_null_tables= nested_join->not_null_tables;
}
else
{
used_tables= table->table->map;
if (conds)
not_null_tables= conds->not_null_tables();
}
if (table->embedding)
{
table->embedding->nested_join->used_tables|= used_tables;
table->embedding->nested_join->not_null_tables|= not_null_tables;
}
if (!table->outer_join || (used_tables & not_null_tables))
{
/*
For some of the inner tables there are conjunctive predicates
that reject nulls => the outer join can be replaced by an inner join.
*/
table->outer_join= 0;
if (table->on_expr)
{
/* Add on expression to the where condition. */
if (conds)
{
conds= and_conds(conds, table->on_expr);
conds->fix_fields(join->thd, 0, &conds);
}
else
conds= table->on_expr;
table->on_expr= 0;
}
}
if (!top)
continue;
/*
Only inner tables of non-convertible outer joins
remain with on_expr.
*/
if (table->on_expr)
{
table->dep_tables|= table->on_expr->used_tables();
if (table->embedding)
{
table->dep_tables&= ~table->embedding->nested_join->used_tables;
/*
Embedding table depends on tables used
in embedded on expressions.
*/
table->embedding->on_expr_dep_tables|= table->on_expr->used_tables();
}
else
table->dep_tables&= ~table->table->map;
}
if (prev_table)
{
/* The order of tables is reverse: prev_table follows table */
if (prev_table->straight)
prev_table->dep_tables|= used_tables;
if (prev_table->on_expr)
prev_table->dep_tables|= table->on_expr_dep_tables;
}
prev_table= table;
}
/* Flatten nested joins that can be flattened. */
li.rewind();
while((table= li++))
{
nested_join= table->nested_join;
if (nested_join && !table->on_expr)
{
TABLE_LIST *tbl;
List_iterator<TABLE_LIST> it(nested_join->join_list);
while ((tbl= it++))
{
tbl->embedding= table->embedding;
tbl->join_list= table->join_list;
}
li.replace(nested_join->join_list);
}
}
return conds;
}
static COND *
optimize_cond(COND *conds,Item::cond_result *cond_value)
{
......@@ -4567,7 +5019,6 @@ const_expression_in_where(COND *cond, Item *comp_item, Item **const_item)
return 0;
}
/****************************************************************************
Create internal temporary table
****************************************************************************/
......@@ -5587,7 +6038,7 @@ do_select(JOIN *join,List<Item> *fields,TABLE *table,Procedure *procedure)
if (join->tables == join->const_tables)
{
/*
HAVING will be chcked after processing aggregate functions,
HAVING will be checked after processing aggregate functions,
But WHERE should checkd here (we alredy have read tables)
*/
if (!join->conds || join->conds->val_int())
......@@ -5675,21 +6126,144 @@ sub_select_cache(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
return sub_select(join,join_tab,end_of_records); /* Use ordinary select */
}
/*
Retrieve records ends with a given beginning from the result of a join
SYNPOSIS
sub_select()
join pointer to the structure providing all context info for the query
join_tab the first next table of the execution plan to be retrieved
end_records true when we need to perform final steps of retrival
DESCRIPTION
For a given partial join record consisting of records from the tables
preceding the table join_tab in the execution plan, the function
retrieves all matching full records from the result set and
send them to the result set stream.
NOTES
The function effectively implements the final (n-k) nested loops
of nested loops join algorithm, where k is the ordinal number of
the join_tab table and n is the total number of tables in the join query.
It performs nested loops joins with all conjunctive predicates from
the where condition pushed as low to the tables as possible.
E.g. for the query
SELECT * FROM t1,t2,t3
WHERE t1.a=t2.a AND t2.b=t3.b AND t1.a BETWEEN 5 AND 9
the predicate (t1.a BETWEEN 5 AND 9) will be pushed to table t1,
given the selected plan prescribes to nest retrievals of the
joined tables in the following order: t1,t2,t3.
A pushed down predicate are attached to the table which it pushed to,
at the field select_cond.
When executing a nested loop of level k the function runs through
the rows of 'join_tab' and for each row checks the pushed condition
attached to the table.
If it is false the function moves to the next row of the
table. If the condition is true the function recursively executes (n-k-1)
remaining embedded nested loops.
The situation becomes more complicated if outer joins are involved in
the execution plan. In this case the pushed down predicates can be
checked only at certain conditions.
Suppose for the query
SELECT * FROM t1 LEFT JOIN (t2,t3) ON t3.a=t1.a
WHERE t1>2 AND (t2.b>5 OR t2.b IS NULL)
the optimizer has chosen a plan with the table order t1,t2,t3.
The predicate P1=t1>2 will be pushed down to the table t1, while the
predicate P2=(t2.b>5 OR t2.b IS NULL) will be attached to the table
t2. But the second predicate can not be unconditionally tested right
after a row from t2 has been read. This can be done only after the
first row with t3.a=t1.a has been encountered.
Thus, the second predicate P2 is supplied with a guarded value that are
stored in the field 'found' of the first inner table for the outer join
(table t2). When the first row with t3.a=t1.a for the current row
of table t1 appears, the value becomes true. For now on the predicate
is evaluated immediately after the row of table t2 has been read.
When the first row with t3.a=t1.a has been encountered all
conditions attached to the inner tables t2,t3 must be evaluated.
Only when all of them are true the row is sent to the output stream.
If not, the function returns to the lowest nest level that has a false
attached condition.
The predicates from on expressions are also pushed down. If in the
the above example the on expression were (t3.a=t1.a AND t2.a=t1.a),
then t1.a=t2.a would be pushed down to table t2, and without any
guard.
If after the run through all rows of table t2, the first inner table
for the outer join operation, it turns out that no matches are
found for the current row of t1, then current row from table t1
is complemented by nulls for t2 and t3. Then the pushed down predicates
are checked for the composed row almost in the same way as it had
been done for the first row with a match. The only difference is
the predicates from on expressions are not checked.
IMPLEMENTATION
The function forms output rows for a current partial join of k
tables tables recursively.
For each partial join record ending with a certain row from
join_tab it calls sub_select that builds all possible matching
tails from the result set.
To be able check predicates conditionally items of the class
Item_func_trig_cond are employed.
An object of this class is constructed from an item of class COND
and a pointer to a guarding boolean variable.
When the value of the guard variable is true the value of the object
is the same as the value of the predicate, otherwise it's just returns
true.
To carry out a return to a nested loop level of join table t the pointer
to t is remembered in the field 'return_tab' of the join structure.
Consider the following query:
SELECT * FROM t1,
LEFT JOIN
(t2, t3 LEFT JOIN (t4,t5) ON t5.a=t3.a)
ON t4.a=t2.a
WHERE (t2.b=5 OR t2.b IS NULL) AND (t4.b=2 OR t4.b IS NULL)
Suppose the chosen execution plan dictates the order t1,t2,t3,t4,t5
and suppose for a given joined rows from tables t1,t2,t3 there are
no rows in the result set yet.
When first row from t5 that satisfies the on condition
t5.a=t3.a is found, the pushed down predicate t4.b=2 OR t4.b IS NULL
becomes 'activated', as well the predicate t4.a=t2.a. But
the predicate (t2.b=5 OR t2.b IS NULL) can not be checked until
t4.a=t2.a becomes true.
In order not to re-evaluate the predicates that were already evaluated
as attached pushed down predicates, a pointer to the the first
most inner unmatched table is maintained in join_tab->first_unmatched.
Thus, when the first row from t5 with t5.a=t3.a is found
this pointer for t5 is changed from t4 to t2.
RETURN
0, if success
# of the error, otherwise
*/
static int
sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
{
join_tab->table->null_row=0;
if (end_of_records)
return (*join_tab->next_select)(join,join_tab+1,end_of_records);
/* Cache variables for faster loop */
int error;
bool found=0;
COND *on_expr=join_tab->on_expr, *select_cond=join_tab->select_cond;
JOIN_TAB *first_unmatched;
JOIN_TAB *tab;
bool found= 0;
/* Cache variables for faster loop */
COND *select_cond= join_tab->select_cond;
JOIN_TAB *first_inner_tab= join_tab->first_inner;
my_bool *report_error= &(join->thd->net.report_error);
if (join_tab->last_inner)
{ /* join_tab is the first inner table for an outer join operation. */
/* Set initial state of guard variables for this table.*/
join_tab->found=0;
join_tab->not_null_compl= 1;
/* Set first_unmatched for the last inner table of this group */
join_tab->last_inner->first_unmatched= join_tab;
}
if (!(error=(*join_tab->read_first_record)(join_tab)))
{
bool not_exists_optimize= join_tab->table->reginfo.not_exists_optimize;
......@@ -5705,17 +6279,83 @@ sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
join->thd->send_kill_message();
return -2; /* purecov: inspected */
}
if (!select_cond || select_cond->val_int())
{
/*
There is no select condition or the attached pushed down
condition is true => a match is found.
*/
bool found= 1;
while (join_tab->first_unmatched && found)
{
/*
The while condition is always false if join_tab is not
the last inner join table of an outer join operation.
*/
first_unmatched= join_tab->first_unmatched;
/*
Mark that a match for current outer table is found.
This activates push down conditional predicates attached
to the all inner tables of the outer join.
*/
first_unmatched->found= 1;
for (tab= first_unmatched; tab <= join_tab; tab++)
{
/* Check all predicates that has just been activated. */
/*
Actually all predicates non-guarded by first_unmatched->found
will be re-evaluated again. It could be fixed, but, probably,
it's not worth doing now.
*/
if (tab->select_cond && !tab->select_cond->val_int())
{
/* The condition attached to table tab is false */
if (tab == join_tab)
found= 0;
else
{
/*
Set a return point if rejected predicate is attached
not to the last table of the current nest level.
*/
join->return_tab= tab;
return 0;
}
}
}
/*
Check whether join_tab is not the last inner table
for another embedding outer join.
*/
if ((first_unmatched= first_unmatched->first_upper) &&
first_unmatched->last_inner != join_tab)
first_unmatched= 0;
join_tab->first_unmatched= first_unmatched;
}
/*
It was not just a return to lower loop level when one
of the newly activated predicates is evaluated as false
(See above join->return_tab= tab).
*/
join->examined_rows++;
join->thd->row_count++;
if (!on_expr || on_expr->val_int())
if (found)
{
found=1;
if (not_exists_optimize)
break; // Searching after not null columns
if (!select_cond || select_cond->val_int())
{
if ((error=(*join_tab->next_select)(join,join_tab+1,0)) < 0)
break;
/* A match from join_tab is found for the current partial join. */
if ((error=(*join_tab->next_select)(join, join_tab+1, 0)) < 0)
return error;
if (join->return_tab)
{
/* We are just returning to the nest level of join->return_tab. */
if (join->return_tab != join_tab)
return 0;
/* The return point is reached */
join->return_tab= 0;
}
/*
Test if this was a SELECT DISTINCT query on a table that
was not in the field list; In this case we can abort if
......@@ -5727,21 +6367,77 @@ sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
else
info->file->unlock_row();
}
else
{
/*
The condition pushed down to the table join_tab rejects all rows
with the beginning coinciding with the current partial join.
*/
join->examined_rows++;
join->thd->row_count++;
}
} while (!(error=info->read_record(info)) && !(*report_error));
}
if (error > 0 || (*report_error)) // Fatal error
return -1;
if (!found && on_expr)
{ // OUTER JOIN
if (join_tab->last_inner && !join_tab->found)
{
/*
The table join_tab is the first inner table of a outer join operation
and no matches has been found for the current outer row.
*/
JOIN_TAB *last_inner_tab= join_tab->last_inner;
for ( ; join_tab <= last_inner_tab ; join_tab++)
{
/* Change the the values of guard predicate variables. */
join_tab->found= 1;
join_tab->not_null_compl= 0;
/* The outer row is complemented by nulls for each inner tables */
restore_record(join_tab->table,default_values); // Make empty record
mark_as_null_row(join_tab->table); // For group by without error
if (!select_cond || select_cond->val_int())
select_cond= join_tab->select_cond;
/* Check all attached conditions for inner table rows. */
if (select_cond && !select_cond->val_int())
return 0;
}
join_tab--;
/*
The row complemented by nulls might be the first row
of embedding outer joins.
If so, perform the same actions as in the code
for the first regular outer join row above.
*/
for ( ; ; )
{
first_unmatched= join_tab->first_unmatched;
if ((first_unmatched= first_unmatched->first_upper) &&
first_unmatched->last_inner != join_tab)
first_unmatched= 0;
join_tab->first_unmatched= first_unmatched;
if (!first_unmatched)
break;
first_unmatched->found= 1;
for (JOIN_TAB *tab= first_unmatched; tab <= join_tab; tab++)
{
if ((error=(*join_tab->next_select)(join,join_tab+1,0)) < 0)
return error; /* purecov: inspected */
if (tab->select_cond && !tab->select_cond->val_int())
{
if (tab != join_tab)
join->return_tab= tab;
return 0;
}
}
}
/*
The row complemented by nulls satisfies all conditions
attached to inner tables.
Send the row complemented by nulls to be joined with the
remaining tables.
*/
if ((error=(*join_tab->next_select)(join, join_tab+1 ,0)) < 0)
return error;
}
return 0;
}
......@@ -7217,6 +7913,8 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
delete select; // filesort did select
tab->select=0;
tab->select_cond=0;
tab->last_inner= 0;
tab->first_unmatched= 0;
tab->type=JT_ALL; // Read with normal read_record
tab->read_first_record= join_init_read_record;
tab->join->examined_rows+=examined_rows;
......@@ -9296,11 +9994,35 @@ void st_select_lex::print(THD *thd, String *str)
if (table_list.elements)
{
str->append(" from ", 6);
Item *next_on= 0;
for (TABLE_LIST *table= (TABLE_LIST *) table_list.first;
table;
table= table->next)
{
TABLE_LIST *embedded=table;
TABLE_LIST *embedding= table->embedding;
while (embedding)
{
TABLE_LIST *next;
NESTED_JOIN *nested_join= table->embedding->nested_join;
List_iterator_fast<TABLE_LIST> it(nested_join->join_list);
TABLE_LIST *tab= it++;
while ((next= it++))
tab= next;
if (tab != embedded)
break;
str->append('(');
if (embedded->outer_join & JOIN_TYPE_RIGHT)
str->append(" right join ", 12);
else if (embedded->outer_join & JOIN_TYPE_LEFT)
str->append(" left join ", 11);
else if (embedded->straight)
str->append(" straight_join ", 15);
else
str->append(" join ", 6);
embedded= embedding;
embedding= embedding->embedding;
}
if (table->derived)
{
str->append('(');
......@@ -9320,35 +10042,43 @@ void st_select_lex::print(THD *thd, String *str)
}
}
if (table->on_expr && ((table->outer_join & JOIN_TYPE_LEFT) ||
!(table->outer_join & JOIN_TYPE_RIGHT)))
next_on= table->on_expr;
if (next_on)
if (table->on_expr)
{
str->append(" on(", 4);
next_on->print(str);
table->on_expr->print(str);
str->append(')');
next_on= 0;
}
TABLE_LIST *next_table;
if ((next_table= table->next))
{
if (table->outer_join & JOIN_TYPE_RIGHT)
{
if (next_table->outer_join & JOIN_TYPE_RIGHT)
str->append(" right join ", 12);
if (!(table->outer_join & JOIN_TYPE_LEFT) &&
table->on_expr)
next_on= table->on_expr;
}
else if (next_table->straight)
str->append(" straight_join ", 15);
else if (next_table->outer_join & JOIN_TYPE_LEFT)
str->append(" left join ", 11);
else if (next_table->straight)
str->append(" straight_join ", 15);
else
str->append(" join ", 6);
}
embedded=table;
embedding= table->embedding;
while (embedding)
{
NESTED_JOIN *nested_join= table->embedding->nested_join;
if (nested_join->join_list.head() != embedded)
break;
str->append(')');
if (embedding->on_expr)
{
str->append(" on(", 4);
embedding->on_expr->print(str);
str->append(')');
}
embedded= embedding;
embedding= embedding->embedding;
}
}
}
......
sql/sql_select.h
View file @ 356cbe4f
......@@ -73,7 +73,6 @@ typedef struct st_join_cache {
/*
** The structs which holds the join connections and join states
*/
enum join_type { JT_UNKNOWN,JT_SYSTEM,JT_CONST,JT_EQ_REF,JT_REF,JT_MAYBE_REF,
JT_ALL, JT_RANGE, JT_NEXT, JT_FT, JT_REF_OR_NULL,
JT_UNIQUE_SUBQUERY, JT_INDEX_SUBQUERY, JT_INDEX_MERGE};
......@@ -86,7 +85,13 @@ typedef struct st_join_table {
SQL_SELECT *select;
COND *select_cond;
QUICK_SELECT_I *quick;
Item *on_expr;
Item *on_expr; /* associated on expression */
st_join_table *first_inner; /* first inner table for including outerjoin */
bool found; /* true after all matches or null complement */
bool not_null_compl;/* true before null complement is added */
st_join_table *last_inner; /* last table table for embedding outer join */
st_join_table *first_upper; /* first inner table for embedding outer join */
st_join_table *first_unmatched; /* used for optimization purposes only */
const char *info;
byte *null_ref_key;
int (*read_first_record)(struct st_join_table *tab);
......@@ -196,8 +201,10 @@ class JOIN :public Sql_alloc
ORDER *order, *group_list, *proc_param; //hold parameters of mysql_select
COND *conds; // ---"---
Item *conds_history; // store WHERE for explain
TABLE_LIST *tables_list; //hold 'tables' parameter of mysql_selec
TABLE_LIST *tables_list; //hold 'tables' parameter of mysql_select
List<TABLE_LIST> *join_list; // list of joined tables in reverse order
SQL_SELECT *select; //created in optimisation phase
JOIN_TAB *return_tab; //used only for outer joins
Item **ref_pointer_array; //used pointer reference for this select
// Copy of above to be used with different lists
Item **items0, **items1, **items2, **items3, **current_ref_pointer_array;
......@@ -221,6 +228,7 @@ class JOIN :public Sql_alloc
table= 0;
tables= 0;
const_tables= 0;
join_list= 0;
sort_and_group= 0;
first_record= 0;
do_send_rows= 1;
......@@ -251,6 +259,7 @@ class JOIN :public Sql_alloc
fields_list= fields_arg;
error= 0;
select= 0;
return_tab= 0;
ref_pointer_array= items0= items1= items2= items3= 0;
ref_pointer_array_size= 0;
zero_result_cause= 0;
......
sql/sql_yacc.yy
View file @ 356cbe4f
......@@ -698,6 +698,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
%type <table_list>
join_table_list join_table
table_factor table_ref
%type <udf>
UDF_CHAR_FUNC UDF_FLOAT_FUNC UDF_INT_FUNC
......@@ -4192,59 +4193,80 @@ when_list2:
sel->when_list.head()->push_back($5);
};
join_table_list:
'(' join_table_list ')' { $$=$2; }
table_ref:
table_factor { $$=$1; }
| join_table { $$=$1; }
| join_table_list ',' join_table_list { $$=$3; }
| join_table_list normal_join join_table_list { $$=$3; }
| join_table_list STRAIGHT_JOIN join_table_list
{ $$=$3 ; $1->next->straight=1; }
| join_table_list normal_join join_table_list ON expr
{
LEX *lex= Lex;
if (!($$= lex->current_select->nest_last_join(lex->thd)))
YYABORT;
}
;
join_table_list:
table_ref { $$=$1; }
| join_table_list ',' table_ref { $$=$3; }
;
join_table:
table_ref normal_join table_ref { $$=$3; }
| table_ref STRAIGHT_JOIN table_factor
{ $3->straight=1; $$=$3 ; }
| table_ref normal_join table_ref ON expr
{ add_join_on($3,$5); $$=$3; }
| join_table_list normal_join join_table_list
| table_ref normal_join table_ref
USING
{
SELECT_LEX *sel= Select;
sel->db1=$1->db; sel->table1=$1->alias;
sel->db2=$3->db; sel->table2=$3->alias;
sel->save_names_for_using_list($1, $3);
}
'(' using_list ')'
{ add_join_on($3,$7); $$=$3; }
| join_table_list LEFT opt_outer JOIN_SYM join_table_list ON expr
| table_ref LEFT opt_outer JOIN_SYM table_ref ON expr
{ add_join_on($5,$7); $5->outer_join|=JOIN_TYPE_LEFT; $$=$5; }
| join_table_list LEFT opt_outer JOIN_SYM join_table_list
| table_ref LEFT opt_outer JOIN_SYM table_ref
{
SELECT_LEX *sel= Select;
sel->db1=$1->db; sel->table1=$1->alias;
sel->db2=$5->db; sel->table2=$5->alias;
sel->save_names_for_using_list($1, $5);
}
USING '(' using_list ')'
{ add_join_on($5,$9); $5->outer_join|=JOIN_TYPE_LEFT; $$=$5; }
| join_table_list NATURAL LEFT opt_outer JOIN_SYM join_table_list
| table_ref NATURAL LEFT opt_outer JOIN_SYM table_factor
{
add_join_natural($1,$1->next);
$1->next->outer_join|=JOIN_TYPE_LEFT;
add_join_natural($1,$6);
$6->outer_join|=JOIN_TYPE_LEFT;
$$=$6;
}
| join_table_list RIGHT opt_outer JOIN_SYM join_table_list ON expr
{ add_join_on($1,$7); $1->outer_join|=JOIN_TYPE_RIGHT; $$=$5; }
| join_table_list RIGHT opt_outer JOIN_SYM join_table_list
| table_ref RIGHT opt_outer JOIN_SYM table_ref ON expr
{
LEX *lex= Lex;
if (!($$= lex->current_select->convert_right_join()))
YYABORT;
add_join_on($$, $7);
}
| table_ref RIGHT opt_outer JOIN_SYM table_ref
{
SELECT_LEX *sel= Select;
sel->db1=$1->db; sel->table1=$1->alias;
sel->db2=$5->db; sel->table2=$5->alias;
sel->save_names_for_using_list($1, $5);
}
USING '(' using_list ')'
{ add_join_on($1,$9); $1->outer_join|=JOIN_TYPE_RIGHT; $$=$5; }
| join_table_list NATURAL RIGHT opt_outer JOIN_SYM join_table_list
{
add_join_natural($1->next,$1);
$1->outer_join|=JOIN_TYPE_RIGHT;
$$=$6;
LEX *lex= Lex;
if (!($$= lex->current_select->convert_right_join()))
YYABORT;
add_join_on($$, $9);
}
| table_ref NATURAL RIGHT opt_outer JOIN_SYM table_factor
{
add_join_natural($6,$1);
LEX *lex= Lex;
if (!($$= lex->current_select->convert_right_join()))
YYABORT;
}
| join_table_list NATURAL JOIN_SYM join_table_list
{ add_join_natural($1,$1->next); $$=$4; };
| table_ref NATURAL JOIN_SYM table_factor
{ add_join_natural($1,$4); $$=$4; };
normal_join:
JOIN_SYM {}
......@@ -4252,7 +4274,7 @@ normal_join:
| CROSS JOIN_SYM {}
;
join_table:
table_factor:
{
SELECT_LEX *sel= Select;
sel->use_index_ptr=sel->ignore_index_ptr=0;
......@@ -4268,8 +4290,21 @@ join_table:
sel->get_use_index(),
sel->get_ignore_index())))
YYABORT;
sel->add_joined_table($$);
}
| '('
{
LEX *lex= Lex;
if (lex->current_select->init_nested_join(lex->thd))
YYABORT;
}
join_table_list ')'
{
LEX *lex= Lex;
if (!($$= lex->current_select->end_nested_join(lex->thd)))
YYABORT;
}
| '{' ident join_table LEFT OUTER JOIN_SYM join_table ON expr '}'
| '{' ident table_ref LEFT OUTER JOIN_SYM table_ref ON expr '}'
{ add_join_on($7,$9); $7->outer_join|=JOIN_TYPE_LEFT; $$=$7; }
| '(' SELECT_SYM select_derived ')' opt_table_alias
{
......@@ -4289,6 +4324,7 @@ join_table:
(List<String> *)0)))
YYABORT;
lex->current_select->add_joined_table($$);
};
select_derived:
......
sql/table.h
View file @ 356cbe4f
......@@ -143,12 +143,8 @@ struct st_table {
uint quick_key_parts[MAX_KEY];
key_part_map const_key_parts[MAX_KEY];
ulong query_id;
union /* Temporary variables */
{
uint temp_pool_slot; /* Used by intern temp tables */
struct st_table_list *pos_in_table_list;
};
struct st_table_list *pos_in_table_list;/* Element referring to this table */
/* number of select if it is derived table */
uint derived_select_number;
THD *in_use; /* Which thread uses this */
......@@ -178,10 +174,24 @@ typedef struct st_table_list
uint32 db_length, real_name_length;
bool straight; /* optimize with prev table */
bool updating; /* for replicate-do/ignore table */
bool force_index; /* Prefer index over table scan */
bool ignore_leaves; /* Preload only non-leaf nodes */
bool force_index; /* prefer index over table scan */
bool ignore_leaves; /* preload only non-leaf nodes */
table_map dep_tables; /* tables the table depends on */
table_map on_expr_dep_tables; /* tables on expression depends on */
struct st_nested_join *nested_join; /* if the element is a nested join */
st_table_list *embedding; /* nested join containing the table */
List<struct st_table_list> *join_list;/* join list the table belongs to */
} TABLE_LIST;
typedef struct st_nested_join
{
List<TABLE_LIST> join_list; /* list of elements in the nested join */
table_map used_tables; /* bitmap of tables in the nested join */
table_map not_null_tables; /* tables that rejects nulls */
struct st_join_table *first_nested;/* the first nested table in the plan */
uint counter; /* to count tables in the nested join */
} NESTED_JOIN;
typedef struct st_changed_table_list
{
struct st_changed_table_list *next;
......@@ -189,8 +199,7 @@ typedef struct st_changed_table_list
uint32 key_length;
} CHANGED_TABLE_LIST;
typedef struct st_open_table_list
{
typedef struct st_open_table_list{
struct st_open_table_list *next;
char *db,*table;
uint32 in_use,locked;
......
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