BUG#928048: Query containing IN subquery with OR in the where clause returns a wrong result

- Make equality propagation work correctly when done inside the OR branches 

mysql-test/r/subselect_mat.result

@@ -1831,6 +1831,23 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 3	MATERIALIZED	alias3	ALL	NULL	NULL	NULL	NULL	2	
 3	MATERIALIZED	alias4	index	c	c	11	NULL	2	Using where; Using index; Using join buffer (flat, BNL join)
 DROP TABLE t1,t2;
+#
+# BUG#928048: Query containing IN subquery with OR in the where clause returns a wrong result
+#
+create table t1 (a int, b int);
+insert into t1 values (7,5), (3,3), (5,4), (9,3);
+create table t2 (a int, b int, index i_a(a));
+insert into t2 values
+(4,2), (7,9), (7,4), (3,1), (5,3), (3,1), (9,4), (8,1);
+explain select * from t1 where t1.a in (select a from t2 where t2.a=7 or t2.b<=1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+2	MATERIALIZED	t2	ALL	i_a	NULL	NULL	NULL	8	Using where
+select * from t1 where t1.a in (select a from t2 where t2.a=7 or t2.b<=1);
+a	b
+7	5
+3	3
+drop table t1,t2;
 # This must be at the end:
 set optimizer_switch=@subselect_sj_mat_tmp;
 set join_cache_level=@save_join_cache_level;

mysql-test/r/subselect_sj_mat.result

@@ -1867,6 +1867,24 @@ WHERE alias4.c = alias3.b
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 DROP TABLE t1,t2;
+#
+# BUG#928048: Query containing IN subquery with OR in the where clause returns a wrong result
+#
+create table t1 (a int, b int);
+insert into t1 values (7,5), (3,3), (5,4), (9,3);
+create table t2 (a int, b int, index i_a(a));
+insert into t2 values
+(4,2), (7,9), (7,4), (3,1), (5,3), (3,1), (9,4), (8,1);
+explain select * from t1 where t1.a in (select a from t2 where t2.a=7 or t2.b<=1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	MATERIALIZED	t2	ALL	i_a	NULL	NULL	NULL	8	Using where
+select * from t1 where t1.a in (select a from t2 where t2.a=7 or t2.b<=1);
+a	b
+7	5
+3	3
+drop table t1,t2;
 # This must be at the end:
 set optimizer_switch=@subselect_sj_mat_tmp;
 set join_cache_level=@save_join_cache_level;

mysql-test/t/subselect_sj_mat.test

@@ -1529,6 +1529,23 @@ WHERE b = a AND a IN (
 
 DROP TABLE t1,t2;
 
+--echo #
+--echo # BUG#928048: Query containing IN subquery with OR in the where clause returns a wrong result
+--echo #
+create table t1 (a int, b int);
+insert into t1 values (7,5), (3,3), (5,4), (9,3);
+
+create table t2 (a int, b int, index i_a(a));
+
+insert into t2 values
+  (4,2), (7,9), (7,4), (3,1), (5,3), (3,1), (9,4), (8,1);
+
+explain select * from t1 where t1.a in (select a from t2 where t2.a=7 or t2.b<=1);
+select * from t1 where t1.a in (select a from t2 where t2.a=7 or t2.b<=1);
+
+drop table t1,t2;
+
+
 --echo # This must be at the end:
 set optimizer_switch=@subselect_sj_mat_tmp;
 set join_cache_level=@save_join_cache_level;

sql/sql_select.cc

@@ -11490,7 +11490,7 @@ Item *eliminate_item_equal(COND *cond, COND_EQUAL *upper_levels,
     }      
 
     /* 
-      Check if "item_field=head" equality is already guaranteed to be true 
+      Check if "field_item=head" equality is already guaranteed to be true 
       on upper AND-levels.
     */
     if (upper)
@@ -11502,7 +11502,8 @@ Item *eliminate_item_equal(COND *cond, COND_EQUAL *upper_levels,
         Item_equal_fields_iterator li(*item_equal);
         while ((item= li++) != field_item)
         {
-          if (item->find_item_equal(upper_levels) == upper)
+          if (embedding_sjm(item) == field_sjm && 
+              item->find_item_equal(upper_levels) == upper)
             break;
         }
       }
@@ -11646,7 +11647,7 @@ static COND* substitute_for_best_equal_field(JOIN_TAB *context_tab,
     if (and_level)
     {
       cond_equal= &((Item_cond_and *) cond)->cond_equal;
-      cond_list->disjoin((List<Item> *) &cond_equal->current_level);
+      cond_list->disjoin((List<Item> *) &cond_equal->current_level);/* remove Item_equal objects from the AND. */
 
       List_iterator_fast<Item_equal> it(cond_equal->current_level);      
       while ((item_equal= it++))