@@ -996,7 +996,7 @@ id select_type table type possible_keys key key_len ref rows filtered Extra
2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort; Distinct
2 DERIVED td ALL NULL NULL NULL NULL 2 100.00 Distinct; Using join buffer
Warnings:
Note 1003 select 1 AS `1` from (select distinct group_concat(`test`.`td`.`f1` separator ',') AS `GROUP_CONCAT(td.f1)` from `test`.`t1` join `test`.`t1` `td` group by `test`.`td`.`f1`) `d` join `test`.`t1`
Note 1003 select 1 AS `1` from `test`.`t1`
SELECT 1 FROM
(SELECT DISTINCT GROUP_CONCAT(td.f1) FROM t1,t1 AS td GROUP BY td.f1) AS d,t1;