purge master logs before (select adddate(current_timestamp(), interval -4 day));
ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'select adddate(current_timestamp(), interval -4 day))' at line 1
purge master logs before adddate(current_timestamp(), interval -4 day);
create table t1(a int,b int,key(a),key(b));
insert into t1(a,b) values (1,2),(2,1),(2,3),(3,4),(5,4),(5,5),
(6,7),(7,4),(5,3);
select sum(a),a from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1
)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1) 
group by a;
sum(a)	a
select sum(a),a from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1) 
group by a;
ERROR HY000: Thread stack overrun detected
explain select sum(a),a from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 
)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1) 
group by a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	index	a	a	5	NULL	9	Using where; Using index
2	SUBQUERY	t1	index	a	b	5	NULL	9	Using where; Using filesort
3	SUBQUERY	t1	index	a	b	5	NULL	9	Using where; Using filesort
4	SUBQUERY	t1	index	a	b	5	NULL	9	Using where; Using filesort
5	SUBQUERY	t1	index	a	b	5	NULL	9	Using where; Using filesort
6	SUBQUERY	t1	index	a	b	5	NULL	9	Using where; Using filesort
7	SUBQUERY	t1	index	a	b	5	NULL	9	Using where; Using filesort
8	SUBQUERY	t1	index	a	b	5	NULL	9	Using where; Using filesort
9	SUBQUERY	t1	index	a	b	5	NULL	9	Using where; Using filesort
10	SUBQUERY	t1	index	a	b	5	NULL	9	Using where; Using filesort
11	SUBQUERY	t1	index	a	b	5	NULL	9	Using where; Using filesort
12	SUBQUERY	t1	range	a	a	5	NULL	1	Using where; Using temporary; Using filesort
13	SUBQUERY	t1	index	NULL	a	5	NULL	9	Using index
explain select sum(a),a from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 where a> ( select sum(a) from t1 where a> (
select sum(a) from t1 
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1
)group by b limit 1)group by b limit 1)group by b limit 1) 
group by a;
ERROR HY000: Thread stack overrun detected
drop table t1;