Fixed bug mdev-4348.

The bug was caused a wrong casting.

mysql-test/r/selectivity.result

@@ -647,4 +647,32 @@ DROP DATABASE dbt3_s001;
 set histogram_type=@save_histogram_type;
 set histogram_size=@save_histogram_size;
 set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+use test;
+#
+# Bug mdev-4348: using view with use_condition_selectivity > 1 
+#
+set @tmp_use_stat_tables=@@use_stat_tables;
+set use_stat_tables='never';
+set optimizer_use_condition_selectivity=3;
+CREATE TABLE t1 (a int, b int);
+INSERT t1 VALUES (7,1), (0,7);
+CREATE ALGORITHM=MERGE VIEW v1 AS SELECT * FROM t1;
+CREATE TABLE t2 (c int, d int, index idx(d));
+INSERT INTO t2 VALUES 
+(0,4), (8,6), (1,3), (8,5), (9,3), (2,2), (6,2),
+(1,9), (6,3), (2,8), (4,1), (0,7), (4,8), (4,5);
+EXPLAIN EXTENDED
+SELECT * FROM v1 INNER JOIN t2 ON ( a = c AND b = d );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+1	SIMPLE	t2	ref	idx	idx	5	test.t1.b	2	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`c` AS `c`,`test`.`t2`.`d` AS `d` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`c` = `test`.`t1`.`a`) and (`test`.`t2`.`d` = `test`.`t1`.`b`))
+SELECT * FROM v1 INNER JOIN t2 ON ( a = c AND b = d );
+a	b	c	d
+0	7	0	7
+DROP VIEW v1;
+DROP TABLE t1,t2;
+set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+set use_stat_tables=@tmp_use_stat_tables;
 set use_stat_tables=@save_use_stat_tables;

mysql-test/r/selectivity_innodb.result

@@ -653,6 +653,34 @@ DROP DATABASE dbt3_s001;
 set histogram_type=@save_histogram_type;
 set histogram_size=@save_histogram_size;
 set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+use test;
+#
+# Bug mdev-4348: using view with use_condition_selectivity > 1 
+#
+set @tmp_use_stat_tables=@@use_stat_tables;
+set use_stat_tables='never';
+set optimizer_use_condition_selectivity=3;
+CREATE TABLE t1 (a int, b int);
+INSERT t1 VALUES (7,1), (0,7);
+CREATE ALGORITHM=MERGE VIEW v1 AS SELECT * FROM t1;
+CREATE TABLE t2 (c int, d int, index idx(d));
+INSERT INTO t2 VALUES 
+(0,4), (8,6), (1,3), (8,5), (9,3), (2,2), (6,2),
+(1,9), (6,3), (2,8), (4,1), (0,7), (4,8), (4,5);
+EXPLAIN EXTENDED
+SELECT * FROM v1 INNER JOIN t2 ON ( a = c AND b = d );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+1	SIMPLE	t2	ref	idx	idx	5	test.t1.b	1	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`c` AS `c`,`test`.`t2`.`d` AS `d` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`c` = `test`.`t1`.`a`) and (`test`.`t2`.`d` = `test`.`t1`.`b`))
+SELECT * FROM v1 INNER JOIN t2 ON ( a = c AND b = d );
+a	b	c	d
+0	7	0	7
+DROP VIEW v1;
+DROP TABLE t1,t2;
+set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+set use_stat_tables=@tmp_use_stat_tables;
 set use_stat_tables=@save_use_stat_tables;
 set optimizer_switch=@save_optimizer_switch_for_selectivity_test;
 SET SESSION STORAGE_ENGINE=DEFAULT;

mysql-test/t/selectivity.test

@@ -237,4 +237,35 @@ set histogram_type=@save_histogram_type;
 set histogram_size=@save_histogram_size;
 set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
 
+use test;
+
+--echo #
+--echo # Bug mdev-4348: using view with use_condition_selectivity > 1 
+--echo #
+
+set @tmp_use_stat_tables=@@use_stat_tables; 
+set use_stat_tables='never';
+set optimizer_use_condition_selectivity=3;
+
+CREATE TABLE t1 (a int, b int);
+INSERT t1 VALUES (7,1), (0,7);
+CREATE ALGORITHM=MERGE VIEW v1 AS SELECT * FROM t1;
+
+CREATE TABLE t2 (c int, d int, index idx(d));
+INSERT INTO t2 VALUES 
+  (0,4), (8,6), (1,3), (8,5), (9,3), (2,2), (6,2),
+  (1,9), (6,3), (2,8), (4,1), (0,7), (4,8), (4,5);
+
+EXPLAIN EXTENDED
+SELECT * FROM v1 INNER JOIN t2 ON ( a = c AND b = d );
+
+SELECT * FROM v1 INNER JOIN t2 ON ( a = c AND b = d );
+
+DROP VIEW v1;
+DROP TABLE t1,t2;
+
+set optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
+set use_stat_tables=@tmp_use_stat_tables; 
+
+
 set use_stat_tables=@save_use_stat_tables;

sql/sql_select.cc

@@ -6962,7 +6962,7 @@ double table_multi_eq_cond_selectivity(JOIN *join, uint idx, JOIN_TAB *s,
             Item *ref_item= keyuse->val;
 	    if (ref_item->real_item()->type() == Item::FIELD_ITEM)
 	    {
-              Item_field *field_item= (Item_field *) ref_item;
+              Item_field *field_item= (Item_field *) (ref_item->real_item());
               if (item_equal->contains(field_item->field))
                 adjust_sel= FALSE;              
 	    }