explain extended (select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1)) union (select * from t4 where t4.b=(select max(t2.a)*4 from t2) order by a);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where
2 SUBQUERY t3 ALL NULL NULL NULL NULL 3 Using filesort
3 UNION t4 ALL NULL NULL NULL NULL 3 Using where; Using filesort
3 UNION t4 ALL NULL NULL NULL NULL 3 Using where
4 SUBQUERY t2 ALL NULL NULL NULL NULL 2
NULL UNION RESULT <union1,3> ALL NULL NULL NULL NULL NULL
Warnings:
Note 1003 (select test.t2.a AS `a`,test.t2.b AS `b` from test.t2 where (test.t2.b = (select test.t3.a AS `a` from test.t3 order by test.t3.a desc limit 1))) union (select test.t4.a AS `a`,test.t4.b AS `b` from test.t4 where (test.t4.b = (select (max(test.t2.a) * 4) AS `max(t2.a)*4` from test.t2)) order by test.t4.a)
Note 1003 (select test.t2.a AS `a`,test.t2.b AS `b` from test.t2 where (test.t2.b = (select test.t3.a AS `a` from test.t3 order by test.t3.a desc limit 1))) union (select test.t4.a AS `a`,test.t4.b AS `b` from test.t4 where (test.t4.b = (select (max(test.t2.a) * 4) AS `max(t2.a)*4` from test.t2)) order by a)
select (select a from t3 where a<t2.a*4 order by 1 desc limit 1), a from t2;
(select a from t3 where a<t2.a*4 order by 1 desc limit 1) a