Fixed bug mdev-3913.

The wrong result set returned by the left join query  from
the bug test case happened due to several inconsistencies 
and bugs of the legacy mysql code.

The bug test case uses an execution plan that employs a scan
of a materialized IN subquery from the WHERE condition.
When materializing such an IN- subquery the optimizer injects
additional equalities  into the WHERE clause. These equalities
express the constraints imposed by the subquery predicate.
The injected equality of the query in the  test case happens
to belong to the same equality class, and a new equality 
imposing a condition on the rows of the materialized subquery
is inferred from this class. Simultaneously the multiple
equality is added to the ON expression of the LEFT JOIN
used in the main query.
  
The inferred equality of the form f1=f2 is taken into account
when optimizing the scan of  the rows the temporary table 
that is the result of the subquery materialization: only the 
values of the field f1 are read from the table into the record 
buffer. Meanwhile the inferred equality is removed from the
WHERE conditions altogether as a constraint on the fields
of the temporary table that has been used when filling this table. 
This equality is supposed to be removed from the ON expression
when the multiple equalities of the ON expression are converted
into an optimal set of equality predicates. It supposed to be
removed from the ON expression as an equality inferred from only
equalities of the WHERE condition. Yet, it did not happened
due to the following bug in the code.

Erroneously the code tried to build multiple equality for ON
expression twice: the first time, when it called optimize_cond()
for the WHERE condition, the second time, when it called
this function for the HAVING condition. When executing
optimize_con() for the WHERE condition  a reference
to the multiple equality of the WHERE condition is set
in the multiple equality of the  ON expression. This reference
would allow later to convert multiple equalities of the
ON expression into equality predicates. However the 
the second call of build_equal_items() for the ON expression
that happened when optimize_cond() was called for the
HAVING condition reset this reference to NULL.

This bug fix blocks calling build_equal_items() for ON
expressions for the second time. In general, it will be
beneficial for many queries as it removes from ON 
expressions any equalities that are to be checked for the
WHERE condition.
The patch also fixes two bugs in the list manipulation
operations and a bug in the function  
substitute_for_best_equal_field() that resulted
in passing wrong reference to the multiple equalities
of where conditions when processing multiple
equalities  of ON expressions.

The code of substitute_for_best_equal_field() and
the code the helper function eliminate_item_equal()
were also streamlined and cleaned up.
Now the conversion of the multiple equalities into
an optimal set of equality predicates first produces
the sequence of the all equalities processing multiple
equalities one by one, and, only after this, it inserts
the equalities at the beginning of the other conditions.

The multiple changes in the output of EXPLAIN
EXTENDED are mainly the result of this streamlining,
but in some cases is the result of the removal of
unneeded equalities from ON expressions. In
some test cases this removal were reflected in the
output of EXPLAIN resulted in disappearance of 
“Using where” in some rows of the execution plans.

mysql-test/r/func_group.result

@@ -1851,7 +1851,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	range	a	a	4	NULL	4	100.00	Using where; Using index; Using join buffer (flat, BNL join)
 2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
 Warnings:
-Note	1003	select max(`test`.`t1`.`a`) AS `MAX(a)` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`b` = 2) and (`test`.`t2`.`a` = 1) and (`test`.`t1`.`a` < 10))
+Note	1003	select max(`test`.`t1`.`a`) AS `MAX(a)` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`a` = 1) and (`test`.`t2`.`b` = 2) and (`test`.`t1`.`a` < 10))
 SELECT MAX(a) FROM t1 WHERE (1,2) IN (SELECT a,b FROM t2 WHERE b<5) and a<10;
 MAX(a)
 NULL

mysql-test/r/group_min_max.result

@@ -1714,7 +1714,7 @@ explain extended select distinct a1,a2,b,c from t1 where (a2 >= 'b') and (b = 'a
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	index	NULL	idx_t1_1	163	NULL	128	50.78	Using where; Using index
 Warnings:
-Note	1003	select distinct `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`c` = 'i121') and (`test`.`t1`.`b` = 'a') and (`test`.`t1`.`a2` >= 'b'))
+Note	1003	select distinct `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`b` = 'a') and (`test`.`t1`.`c` = 'i121') and (`test`.`t1`.`a2` >= 'b'))
 explain select distinct a1,a2,b from t1 where (a1 > 'a') and (a2 > 'a') and (b = 'c');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	idx_t1_0,idx_t1_1,idx_t1_2	idx_t1_1	147	NULL	14	Using where; Using index for group-by
@@ -1731,7 +1731,7 @@ explain extended select distinct a1,a2,b,c from t2 where (a2 >= 'b') and (b = 'a
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t2	index	NULL	idx_t2_1	163	NULL	164	50.61	Using where; Using index
 Warnings:
-Note	1003	select distinct `test`.`t2`.`a1` AS `a1`,`test`.`t2`.`a2` AS `a2`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t2` where ((`test`.`t2`.`c` = 'i121') and (`test`.`t2`.`b` = 'a') and (`test`.`t2`.`a2` >= 'b'))
+Note	1003	select distinct `test`.`t2`.`a1` AS `a1`,`test`.`t2`.`a2` AS `a2`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t2` where ((`test`.`t2`.`b` = 'a') and (`test`.`t2`.`c` = 'i121') and (`test`.`t2`.`a2` >= 'b'))
 explain select distinct a1,a2,b from t2 where (a1 > 'a') and (a2 > 'a') and (b = 'c');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	range	idx_t2_0,idx_t2_1,idx_t2_2	idx_t2_1	146	NULL	#	Using where; Using index for group-by

mysql-test/r/having.result

@@ -473,7 +473,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	table2	const	PRIMARY	PRIMARY	4	const	1	100.00	Using filesort
 1	SIMPLE	table1	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
-Note	1003	select `test`.`table1`.`f1` AS `f1`,7 AS `f2` from `test`.`t1` `table1` join `test`.`t1` `table2` where ((`test`.`table1`.`f3` = 9)) group by `test`.`table1`.`f1`,7 having ((7 = 8) and (`test`.`table1`.`f1` >= 6))
+Note	1003	select `test`.`table1`.`f1` AS `f1`,7 AS `f2` from `test`.`t1` `table1` join `test`.`t1` `table2` where (`test`.`table1`.`f3` = 9) group by `test`.`table1`.`f1`,7 having ((7 = 8) and (`test`.`table1`.`f1` >= 6))
 EXPLAIN EXTENDED
 SELECT table1.f1, table2.f2
 FROM t1 AS table1
@@ -485,7 +485,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	table2	const	PRIMARY	PRIMARY	4	const	1	100.00	Using filesort
 1	SIMPLE	table1	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
-Note	1003	select `test`.`table1`.`f1` AS `f1`,7 AS `f2` from `test`.`t1` `table1` join `test`.`t1` `table2` where ((`test`.`table1`.`f3` = 9)) group by `test`.`table1`.`f1`,7 having (7 = 8)
+Note	1003	select `test`.`table1`.`f1` AS `f1`,7 AS `f2` from `test`.`t1` `table1` join `test`.`t1` `table2` where (`test`.`table1`.`f3` = 9) group by `test`.`table1`.`f1`,7 having (7 = 8)
 DROP TABLE t1;
 #
 # Bug#52336 Segfault / crash in 5.1 copy_fields (param=0x9872980) at sql_select.cc:15355

mysql-test/r/row.result

@@ -405,7 +405,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	index	PRIMARY	PRIMARY	8	NULL	6	100.00	Using index
 1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	12	test.t1.a,const,const	1	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`c` = 1) and (`test`.`t2`.`b` = 2) and (`test`.`t2`.`a` = `test`.`t1`.`a`))
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t2`.`b` = 2) and (`test`.`t2`.`c` = 1))
 SELECT * FROM t1,t2 WHERE (t2.a,(t2.b,t2.c))=(t1.a,(2,1));
 a	b	a	b	c
 1	1	1	2	1
@@ -415,7 +415,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	index	PRIMARY	PRIMARY	8	NULL	6	100.00	Using index
 1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	12	test.t1.a,const,const	1	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`c` = 1) and (`test`.`t2`.`b` = 2) and (`test`.`t2`.`a` = `test`.`t1`.`a`))
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t2`.`b` = 2) and (`test`.`t2`.`c` = 1))
 SELECT * FROM t1,t2 WHERE t2.a=t1.a AND (t2.b,t2.c)=(2,1);
 a	b	a	b	c
 1	1	1	2	1

mysql-test/r/subselect.result

@@ -1460,7 +1460,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	75.00	Using where; Using join buffer (flat, BNL join)
 1	PRIMARY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.b	1	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t3` join `test`.`t2` where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t3`.`a` = `test`.`t1`.`b`))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t3` join `test`.`t2` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (`test`.`t1`.`a` = `test`.`t2`.`a`))
 drop table t1, t2, t3;
 create table t1 (a int, b int, index a (a,b));
 create table t2 (a int, index a (a));
@@ -1503,7 +1503,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	index	a	a	5	NULL	3	100.00	Using where; Using index
 1	PRIMARY	t1	ref	a	a	10	test.t2.a,test.t3.a	116	100.00	Using index; FirstMatch(t2)
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` = `test`.`t3`.`a`))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`b` = `test`.`t3`.`a`) and (`test`.`t1`.`a` = `test`.`t2`.`a`))
 insert into t1 values (3,31);
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a
@@ -2976,7 +2976,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	8	func,func	1	100.00	
 2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`flag` = 'N'))
+Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where (`test`.`t2`.`flag` = 'N')
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	

mysql-test/r/subselect3.result

@@ -313,7 +313,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t1	index_subquery	idx	idx	5	func	4	100.00	Using where; Full scan on NULL key
 Warnings:
 Note	1276	Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t2`.`oref` AS `oref`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,<expr_cache><`test`.`t2`.`a`,`test`.`t2`.`b`,`test`.`t2`.`oref`>(<in_optimizer>((`test`.`t2`.`a`,`test`.`t2`.`b`),<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on idx checking NULL where ((`test`.`t1`.`oref` = `test`.`t2`.`oref`) and trigcond(((<cache>(`test`.`t2`.`a`) = `test`.`t1`.`ie1`) or isnull(`test`.`t1`.`ie1`))) and trigcond(((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`ie2`) or isnull(`test`.`t1`.`ie2`)))) having (trigcond(<is_not_null_test>(`test`.`t1`.`ie1`)) and trigcond(<is_not_null_test>(`test`.`t1`.`ie2`))))))) AS `Z` from `test`.`t2` where ((`test`.`t2`.`b` = 10) and (`test`.`t2`.`a` = 10))
+Note	1003	select `test`.`t2`.`oref` AS `oref`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,<expr_cache><`test`.`t2`.`a`,`test`.`t2`.`b`,`test`.`t2`.`oref`>(<in_optimizer>((`test`.`t2`.`a`,`test`.`t2`.`b`),<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on idx checking NULL where ((`test`.`t1`.`oref` = `test`.`t2`.`oref`) and trigcond(((<cache>(`test`.`t2`.`a`) = `test`.`t1`.`ie1`) or isnull(`test`.`t1`.`ie1`))) and trigcond(((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`ie2`) or isnull(`test`.`t1`.`ie2`)))) having (trigcond(<is_not_null_test>(`test`.`t1`.`ie1`)) and trigcond(<is_not_null_test>(`test`.`t1`.`ie2`))))))) AS `Z` from `test`.`t2` where ((`test`.`t2`.`a` = 10) and (`test`.`t2`.`b` = 10))
 drop table t1, t2;
 create table t1 (oref char(4), grp int, ie int);
 insert into t1 (oref, grp, ie) values
@@ -1416,7 +1416,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	c	eq_ref	PRIMARY	PRIMARY	4	test.cona.idContact	1	100.00	Using where
 1	PRIMARY	a	eq_ref	PRIMARY	PRIMARY	4	test.c.idObj	1	100.00	Using index; End temporary
 Warnings:
-Note	1003	select `test`.`a`.`idIndividual` AS `idIndividual` from `test`.`t1` `a` semi join (`test`.`t3` `cona` join `test`.`t2` `c`) where ((`test`.`c`.`idContact` = `test`.`cona`.`idContact`) and (`test`.`a`.`idIndividual` = `test`.`c`.`idObj`) and (`test`.`cona`.`postalStripped` = 'T2H3B2'))
+Note	1003	select `test`.`a`.`idIndividual` AS `idIndividual` from `test`.`t1` `a` semi join (`test`.`t3` `cona` join `test`.`t2` `c`) where ((`test`.`cona`.`postalStripped` = 'T2H3B2') and (`test`.`a`.`idIndividual` = `test`.`c`.`idObj`) and (`test`.`c`.`idContact` = `test`.`cona`.`idContact`))
 set @@optimizer_switch=@save_optimizer_switch;
 drop table t1,t2,t3;
 #

mysql-test/r/subselect3_jcl6.result

@@ -323,7 +323,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t1	index_subquery	idx	idx	5	func	4	100.00	Using where; Full scan on NULL key
 Warnings:
 Note	1276	Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t2`.`oref` AS `oref`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,<expr_cache><`test`.`t2`.`a`,`test`.`t2`.`b`,`test`.`t2`.`oref`>(<in_optimizer>((`test`.`t2`.`a`,`test`.`t2`.`b`),<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on idx checking NULL where ((`test`.`t1`.`oref` = `test`.`t2`.`oref`) and trigcond(((<cache>(`test`.`t2`.`a`) = `test`.`t1`.`ie1`) or isnull(`test`.`t1`.`ie1`))) and trigcond(((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`ie2`) or isnull(`test`.`t1`.`ie2`)))) having (trigcond(<is_not_null_test>(`test`.`t1`.`ie1`)) and trigcond(<is_not_null_test>(`test`.`t1`.`ie2`))))))) AS `Z` from `test`.`t2` where ((`test`.`t2`.`b` = 10) and (`test`.`t2`.`a` = 10))
+Note	1003	select `test`.`t2`.`oref` AS `oref`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,<expr_cache><`test`.`t2`.`a`,`test`.`t2`.`b`,`test`.`t2`.`oref`>(<in_optimizer>((`test`.`t2`.`a`,`test`.`t2`.`b`),<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on idx checking NULL where ((`test`.`t1`.`oref` = `test`.`t2`.`oref`) and trigcond(((<cache>(`test`.`t2`.`a`) = `test`.`t1`.`ie1`) or isnull(`test`.`t1`.`ie1`))) and trigcond(((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`ie2`) or isnull(`test`.`t1`.`ie2`)))) having (trigcond(<is_not_null_test>(`test`.`t1`.`ie1`)) and trigcond(<is_not_null_test>(`test`.`t1`.`ie2`))))))) AS `Z` from `test`.`t2` where ((`test`.`t2`.`a` = 10) and (`test`.`t2`.`b` = 10))
 drop table t1, t2;
 create table t1 (oref char(4), grp int, ie int);
 insert into t1 (oref, grp, ie) values
@@ -1426,7 +1426,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	c	eq_ref	PRIMARY	PRIMARY	4	test.cona.idContact	1	100.00	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 1	PRIMARY	a	eq_ref	PRIMARY	PRIMARY	4	test.c.idObj	1	100.00	Using index; End temporary
 Warnings:
-Note	1003	select `test`.`a`.`idIndividual` AS `idIndividual` from `test`.`t1` `a` semi join (`test`.`t3` `cona` join `test`.`t2` `c`) where ((`test`.`c`.`idContact` = `test`.`cona`.`idContact`) and (`test`.`a`.`idIndividual` = `test`.`c`.`idObj`) and (`test`.`cona`.`postalStripped` = 'T2H3B2'))
+Note	1003	select `test`.`a`.`idIndividual` AS `idIndividual` from `test`.`t1` `a` semi join (`test`.`t3` `cona` join `test`.`t2` `c`) where ((`test`.`cona`.`postalStripped` = 'T2H3B2') and (`test`.`a`.`idIndividual` = `test`.`c`.`idObj`) and (`test`.`c`.`idContact` = `test`.`cona`.`idContact`))
 set @@optimizer_switch=@save_optimizer_switch;
 drop table t1,t2,t3;
 #

mysql-test/r/subselect_mat.result

@@ -1896,7 +1896,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	3	100.00	
 Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from  <materialize> (select max(`test`.`t2`.`c`) from `test`.`t2`) join `test`.`t1` where ((`test`.`t1`.`a` = `<subquery2>`.`MAX(c)`) and (`test`.`t1`.`b` = 7) and (isnull(`<subquery2>`.`MAX(c)`) or (`<subquery2>`.`MAX(c)` = 7)))
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from  <materialize> (select max(`test`.`t2`.`c`) from `test`.`t2`) join `test`.`t1` where ((`test`.`t1`.`b` = 7) and (`test`.`t1`.`a` = `<subquery2>`.`MAX(c)`) and (isnull(`<subquery2>`.`MAX(c)`) or (`<subquery2>`.`MAX(c)` = 7)))
 SELECT * FROM t1
 WHERE a IN (SELECT MAX(c) FROM t2) AND b=7 AND (a IS NULL OR a=b);
 a	b

mysql-test/r/subselect_mat_cost_bugs.result

@@ -100,7 +100,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	index	c3	c3	9	NULL	2	100.00	Using where; Using index; Using join buffer (flat, BNL join)
 Warnings:
 Note	1276	Field or reference 'test.t1.pk' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` where <expr_cache><`test`.`t1`.`c1`,`test`.`t1`.`pk`>(<in_optimizer>(`test`.`t1`.`c1`,<exists>(select `test`.`t1a`.`c1` from `test`.`t1b` join `test`.`t2` left join `test`.`t1a` on((2 and (`test`.`t1a`.`c2` = `test`.`t1b`.`pk`))) where ((`test`.`t1`.`pk` <> 0) and (<cache>(`test`.`t1`.`c1`) = `test`.`t1a`.`c1`) and (`test`.`t2`.`c3` = `test`.`t1b`.`c4`)))))
+Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` where <expr_cache><`test`.`t1`.`c1`,`test`.`t1`.`pk`>(<in_optimizer>(`test`.`t1`.`c1`,<exists>(select `test`.`t1a`.`c1` from `test`.`t1b` join `test`.`t2` left join `test`.`t1a` on(((`test`.`t1a`.`c2` = `test`.`t1b`.`pk`) and 2)) where ((`test`.`t1`.`pk` <> 0) and (<cache>(`test`.`t1`.`c1`) = `test`.`t1a`.`c1`) and (`test`.`t2`.`c3` = `test`.`t1b`.`c4`)))))
 SELECT pk
 FROM t1
 WHERE c1 IN

mysql-test/r/subselect_no_mat.result

@@ -1467,7 +1467,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	75.00	Using where; Using join buffer (flat, BNL join)
 1	PRIMARY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.b	1	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t3` join `test`.`t2` where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t3`.`a` = `test`.`t1`.`b`))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t3` join `test`.`t2` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (`test`.`t1`.`a` = `test`.`t2`.`a`))
 drop table t1, t2, t3;
 create table t1 (a int, b int, index a (a,b));
 create table t2 (a int, index a (a));
@@ -1510,7 +1510,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	index	a	a	5	NULL	3	100.00	Using where; Using index
 1	PRIMARY	t1	ref	a	a	10	test.t2.a,test.t3.a	116	100.00	Using index; FirstMatch(t2)
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` = `test`.`t3`.`a`))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`b` = `test`.`t3`.`a`) and (`test`.`t1`.`a` = `test`.`t2`.`a`))
 insert into t1 values (3,31);
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a
@@ -2982,7 +2982,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; FirstMatch(t1)
 Warnings:
-Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`two` = `test`.`t1`.`two`) and (`test`.`t2`.`one` = `test`.`t1`.`one`) and (`test`.`t2`.`flag` = 'N'))
+Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`flag` = 'N') and (`test`.`t2`.`one` = `test`.`t1`.`one`) and (`test`.`t2`.`two` = `test`.`t1`.`two`))
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	

mysql-test/r/subselect_no_scache.result

@@ -1466,7 +1466,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	75.00	Using where; Using join buffer (flat, BNL join)
 1	PRIMARY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.b	1	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t3` join `test`.`t2` where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t3`.`a` = `test`.`t1`.`b`))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t3` join `test`.`t2` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (`test`.`t1`.`a` = `test`.`t2`.`a`))
 drop table t1, t2, t3;
 create table t1 (a int, b int, index a (a,b));
 create table t2 (a int, index a (a));
@@ -1509,7 +1509,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	index	a	a	5	NULL	3	100.00	Using where; Using index
 1	PRIMARY	t1	ref	a	a	10	test.t2.a,test.t3.a	116	100.00	Using index; FirstMatch(t2)
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` = `test`.`t3`.`a`))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`b` = `test`.`t3`.`a`) and (`test`.`t1`.`a` = `test`.`t2`.`a`))
 insert into t1 values (3,31);
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a
@@ -2982,7 +2982,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	8	func,func	1	100.00	
 2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`flag` = 'N'))
+Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where (`test`.`t2`.`flag` = 'N')
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	

mysql-test/r/subselect_sj2.result

@@ -459,7 +459,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Using where; FirstMatch(t2)
 Warnings:
 Note	1276	Field or reference 'test.t0.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where ((`test`.`t1`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`a` = `test`.`t0`.`a`) and (`test`.`t1`.`a` = `test`.`t0`.`a`))
+Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where ((`test`.`t2`.`a` = `test`.`t0`.`a`) and (`test`.`t1`.`a` = `test`.`t0`.`a`) and (`test`.`t1`.`b` = `test`.`t2`.`b`))
 update t1 set a=3, b=11 where a=4;
 update t2 set b=11 where a=3;
 select * from t0 where t0.a in 

mysql-test/r/subselect_sj2_jcl6.result

@@ -471,7 +471,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Using where; FirstMatch(t2); Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
 Warnings:
 Note	1276	Field or reference 'test.t0.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where ((`test`.`t1`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`a` = `test`.`t0`.`a`) and (`test`.`t1`.`a` = `test`.`t0`.`a`))
+Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where ((`test`.`t2`.`a` = `test`.`t0`.`a`) and (`test`.`t1`.`a` = `test`.`t0`.`a`) and (`test`.`t1`.`b` = `test`.`t2`.`b`))
 update t1 set a=3, b=11 where a=4;
 update t2 set b=11 where a=3;
 # Not anymore:

mysql-test/r/subselect_sj2_mat.result

@@ -461,7 +461,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Using where; FirstMatch(t2)
 Warnings:
 Note	1276	Field or reference 'test.t0.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where ((`test`.`t1`.`b` = `test`.`t2`.`b`) and (`test`.`t2`.`a` = `test`.`t0`.`a`) and (`test`.`t1`.`a` = `test`.`t0`.`a`))
+Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where ((`test`.`t2`.`a` = `test`.`t0`.`a`) and (`test`.`t1`.`a` = `test`.`t0`.`a`) and (`test`.`t1`.`b` = `test`.`t2`.`b`))
 update t1 set a=3, b=11 where a=4;
 update t2 set b=11 where a=3;
 select * from t0 where t0.a in 
@@ -1127,3 +1127,55 @@ AND ( 6 ) IN
 ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET MAX_JOIN_SIZE=# if the SELECT is okay
 DROP TABLE t1, t2;
 set max_join_size= @tmp_906385;
+#
+# mdev-3913: LEFT JOIN with materialized multi-table IN subquery in WHERE
+#
+set @save_optimizer_switch=@@optimizer_switch;
+CREATE TABLE t1 (a1 char(1), b1 char(1), index idx(b1,a1));
+INSERT INTO t1 VALUES ('f','c'),('d','m'),('g','y');
+INSERT INTO t1 VALUES ('f','c'),('d','m'),('g','y');
+CREATE TABLE t2 (a2 char(1), b2 char(1));
+INSERT INTO t2 VALUES ('y','y'),('y','y'),('w','w');
+CREATE TABLE t3 (a3 int);
+INSERT INTO t3 VALUES (8),(6);
+CREATE TABLE t4 (a4 char(1), b4 char(1));
+INSERT INTO t4 VALUES ('y','y'),('y','y'),('w','w');
+set optimizer_switch='materialization=off';
+EXPLAIN EXTENDED
+SELECT * FROM t1 LEFT JOIN t2 ON ( b1 = a2 ) 
+WHERE ( b1, b1 )  IN ( SELECT a4, b4 FROM t3, t4);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	Start temporary
+1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	t1	ref	idx	idx	2	test.t4.a4	1	100.00	Using index; End temporary
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
+Warnings:
+Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`b1` AS `b1`,`test`.`t2`.`a2` AS `a2`,`test`.`t2`.`b2` AS `b2` from `test`.`t1` semi join (`test`.`t3` join `test`.`t4`) left join `test`.`t2` on((`test`.`t2`.`a2` = `test`.`t4`.`a4`)) where ((`test`.`t4`.`b4` = `test`.`t4`.`a4`) and (`test`.`t1`.`b1` = `test`.`t4`.`a4`))
+SELECT * FROM t1 LEFT JOIN t2 ON ( b1 = a2 ) 
+WHERE ( b1, b1 )  IN ( SELECT a4, b4 FROM t3, t4);
+a1	b1	a2	b2
+g	y	y	y
+g	y	y	y
+g	y	y	y
+g	y	y	y
+set optimizer_switch='materialization=on';
+EXPLAIN EXTENDED
+SELECT * FROM t1 LEFT JOIN t2 ON ( b1 = a2 ) 
+WHERE ( b1, b1 )  IN ( SELECT a4, b4 FROM t3, t4);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	3	100.00	
+1	PRIMARY	t1	ref	idx	idx	2	test.t4.a4	1	100.00	Using index
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
+2	MATERIALIZED	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	
+2	MATERIALIZED	t4	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
+Warnings:
+Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`b1` AS `b1`,`test`.`t2`.`a2` AS `a2`,`test`.`t2`.`b2` AS `b2` from `test`.`t1` semi join (`test`.`t3` join `test`.`t4`) left join `test`.`t2` on(((`test`.`t1`.`b1` = `test`.`t4`.`a4`) and (`test`.`t2`.`a2` = `test`.`t4`.`a4`))) where ((`test`.`t4`.`b4` = `test`.`t4`.`a4`) and (`test`.`t1`.`b1` = `test`.`t4`.`a4`))
+SELECT * FROM t1 LEFT JOIN t2 ON ( b1 = a2 ) 
+WHERE ( b1, b1 )  IN ( SELECT a4, b4 FROM t3, t4);
+a1	b1	a2	b2
+g	y	y	y
+g	y	y	y
+g	y	y	y
+g	y	y	y
+DROP TABLE t1,t2,t3,t4;
+set optimizer_switch=@save_optimizer_switch;

mysql-test/r/view.result

@@ -1422,7 +1422,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t1`.`a` AS `a`,`test`.`t2`.`a` AS `b` from `test`.`t3` left join (`test`.`t1` left join `test`.`t2` on(((`test`.`t1`.`a` = `test`.`t3`.`a`) and (`test`.`t2`.`a` = `test`.`t3`.`a`)))) on((`test`.`t1`.`a` = `test`.`t3`.`a`)) where 1
+Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t1`.`a` AS `a`,`test`.`t2`.`a` AS `b` from `test`.`t3` left join (`test`.`t1` left join `test`.`t2` on((`test`.`t2`.`a` = `test`.`t3`.`a`))) on((`test`.`t1`.`a` = `test`.`t3`.`a`)) where 1
 create view v1 (a) as select a from t1;
 create view v2 (a) as select a from t2;
 create view v4 (a,b) as select v1.a as a, v2.a as b from v1 left join v2 on (v1.a=v2.a);

mysql-test/t/subselect_sj2_mat.test

@@ -36,4 +36,43 @@ WHERE a IN
 DROP TABLE t1, t2;
 set max_join_size= @tmp_906385;
 
+--echo #
+--echo # mdev-3913: LEFT JOIN with materialized multi-table IN subquery in WHERE
+--echo #
+
+set @save_optimizer_switch=@@optimizer_switch;
+
+CREATE TABLE t1 (a1 char(1), b1 char(1), index idx(b1,a1));
+INSERT INTO t1 VALUES ('f','c'),('d','m'),('g','y');
+INSERT INTO t1 VALUES ('f','c'),('d','m'),('g','y');
+
+CREATE TABLE t2 (a2 char(1), b2 char(1));
+INSERT INTO t2 VALUES ('y','y'),('y','y'),('w','w');
+
+CREATE TABLE t3 (a3 int);
+INSERT INTO t3 VALUES (8),(6);
+
+CREATE TABLE t4 (a4 char(1), b4 char(1));
+INSERT INTO t4 VALUES ('y','y'),('y','y'),('w','w');
+
+set optimizer_switch='materialization=off';
+
+EXPLAIN EXTENDED
+SELECT * FROM t1 LEFT JOIN t2 ON ( b1 = a2 ) 
+  WHERE ( b1, b1 )  IN ( SELECT a4, b4 FROM t3, t4);
+SELECT * FROM t1 LEFT JOIN t2 ON ( b1 = a2 ) 
+  WHERE ( b1, b1 )  IN ( SELECT a4, b4 FROM t3, t4);
+
+set optimizer_switch='materialization=on';
+
+EXPLAIN EXTENDED
+SELECT * FROM t1 LEFT JOIN t2 ON ( b1 = a2 ) 
+  WHERE ( b1, b1 )  IN ( SELECT a4, b4 FROM t3, t4);
+SELECT * FROM t1 LEFT JOIN t2 ON ( b1 = a2 ) 
+  WHERE ( b1, b1 )  IN ( SELECT a4, b4 FROM t3, t4);
+
+DROP TABLE t1,t2,t3,t4;
+
+set optimizer_switch=@save_optimizer_switch;
+
 

sql/item_cmpfunc.h

@@ -1582,6 +1582,11 @@ public:
     DBUG_ASSERT(nlist->elements);
     list.prepand(nlist);
   }
+  void add_at_end(List<Item> *nlist)
+  {
+    DBUG_ASSERT(nlist->elements);
+    list.concat(nlist);
+  }
   bool fix_fields(THD *, Item **ref);
   void fix_after_pullout(st_select_lex *new_parent, Item **ref);
 

sql/sql_list.h

@@ -284,13 +284,15 @@ public:
       if (node == &end_of_list)
         return;
     }
-    *prev= *last;
+    *prev= &end_of_list;
     last= prev;
   }
   inline void prepand(base_list *list)
   {
     if (!list->is_empty())
     {
+      if (is_empty())
+        last= list->last;
       *list->last= first;
       first= list->first;
       elements+= list->elements;