Commit 4bfe1cc8 authored by igor@rurik.mysql.com's avatar igor@rurik.mysql.com

join_nested.result, join_nested.test:

  Added a teast case for bug #11284.
sql_select.cc:
  Fixed bug #11284.
  Optimization with empty inner table currently cannot be
  used in the case of nested outer join.
parent aeb5ab5d
......@@ -1321,3 +1321,25 @@ NULL NULL NULL
18 NULL NULL
19 NULL NULL
DROP TABLE t1,t2,t3;
CREATE TABLE t1 (c11 int);
CREATE TABLE t2 (c21 int);
CREATE TABLE t3 (c31 int);
INSERT INTO t1 VALUES (4), (5);
SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;
c11 c21
4 NULL
5 NULL
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 system NULL NULL NULL NULL 0 const row not found
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;
c11 c21 c31
4 NULL NULL
5 NULL NULL
EXPLAIN SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
1 SIMPLE t2 ALL NULL NULL NULL NULL 0
1 SIMPLE t3 ALL NULL NULL NULL NULL 0
DROP TABLE t1,t2,t3;
......@@ -752,3 +752,21 @@ EXPLAIN SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON b < 3 and b = c;
SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON b < 3 and b = c;
DROP TABLE t1,t2,t3;
#
# Test for bug #11284: empty table in a nested left join
#
CREATE TABLE t1 (c11 int);
CREATE TABLE t2 (c21 int);
CREATE TABLE t3 (c31 int);
INSERT INTO t1 VALUES (4), (5);
SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;
EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;
SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;
EXPLAIN SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;
DROP TABLE t1,t2,t3;
......@@ -2158,7 +2158,7 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables, COND *conds,
if (*s->on_expr_ref)
{
/* s is the only inner table of an outer join */
if (!table->file->records)
if (!table->file->records && !embedding)
{ // Empty table
s->dependent= 0; // Ignore LEFT JOIN depend.
set_position(join,const_count++,s,(KEYUSE*) 0);
......
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