1 files changed, 38 insertions, 0 deletions
diff --git a/mysql-test/t/func_in.test b/mysql-test/t/func_in.test
index 75d85065419..b5afdc122a3 100644
--- a/mysql-test/t/func_in.test
+++ b/mysql-test/t/func_in.test
@@ -261,6 +261,44 @@ select some_id from t1 where some_id not in('-1', '0');
 
 drop table t1;
 
+# TODO:Disabled until re-resolution of bug #20420 for 5.1.
+# Results must be the same as in 5.0
+##
+## BUG#20420: optimizer reports wrong keys on left join with IN
+##
+#CREATE TABLE t1 (a int, b int, PRIMARY KEY (a));
+#INSERT INTO t1 VALUES (1,1),(2,1),(3,1),(4,1),(5,1),(6,1);
+#
+#CREATE TABLE t2 (a int, b int, PRIMARY KEY (a));
+#INSERT INTO t2 VALUES (3,2),(4,2),(100,100),(101,201),(102,102);
+#
+#CREATE TABLE t3 (a int PRIMARY KEY);
+#INSERT INTO t3 VALUES (1),(2),(3),(4);
+#
+#CREATE TABLE t4 (a int PRIMARY KEY,b int);
+#INSERT INTO t4 VALUES (1,1),(2,2),(1000,1000),(1001,1001),(1002,1002),(1003,1003),(1004,1004);
+#
+#EXPLAIN SELECT STRAIGHT_JOIN * FROM t3 
+#  JOIN t1 ON t3.a=t1.a 
+#  JOIN t2 ON t3.a=t2.a
+#  JOIN t4 WHERE t4.a IN (t1.b, t2.b);
+#
+#SELECT STRAIGHT_JOIN * FROM t3 
+#  JOIN t1 ON t3.a=t1.a 
+#  JOIN t2 ON t3.a=t2.a
+#  JOIN t4 WHERE t4.a IN (t1.b, t2.b);
+#
+#EXPLAIN SELECT STRAIGHT_JOIN 
+#   (SELECT SUM(t4.a) FROM t4 WHERE t4.a IN (t1.b, t2.b)) 
+#  FROM t3, t1, t2
+#  WHERE t3.a=t1.a AND t3.a=t2.a;
+#
+#SELECT STRAIGHT_JOIN 
+#   (SELECT SUM(t4.a) FROM t4 WHERE t4.a IN (t1.b, t2.b)) 
+#  FROM t3, t1, t2
+#  WHERE t3.a=t1.a AND t3.a=t2.a;
+#
+#DROP TABLE t1,t2,t3,t4;  
 
 --echo End of 5.0 tests