CREATE TABLE t1(id INT);
INSERT INTO t1 VALUES (1),(2),(3),(4);
INSERT INTO t1 SELECT a.id FROM t1 a,t1 b,t1 c,t1 d;
SET @orig_debug=@@debug;
SET GLOBAL debug_dbug="d,subselect_exec_fail";
SELECT SUM(EXISTS(SELECT RAND() FROM t1)) FROM t1;
SUM(EXISTS(SELECT RAND() FROM t1))
0
SELECT REVERSE(EXISTS(SELECT RAND() FROM t1));
REVERSE(EXISTS(SELECT RAND() FROM t1))
0
SET GLOBAL debug_dbug=@orig_debug;
DROP TABLE t1;
create table t1 (i int);
insert into t1 values (1),(2);
select * from t1 where (i < 200 or i = 300) and i in (select i from t1);
i
1
2
drop table t1;