EXPLAIN EXTENDED SELECT b,c FROM t1 WHERE b = 1 AND CONCAT(b,c) = '0101';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 100.00 Using where
Warnings:
Note 1003 select `test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c` from `test`.`t1` where ((`test`.`t1`.`b` = 1) and (concat(_binary'01',`test`.`t1`.`c`) = _latin1'0101'))
SELECT b,c FROM t1 WHERE b = 1 AND CONCAT(b,c) = '0101';
...
...
@@ -82,9 +82,9 @@ SELECT a,
(SELECT COUNT(*) FROM t1
WHERE b = t2.a AND CONCAT(b,c) = CONCAT('0',t2.a,'01')) x
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 filesort
2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 3 Using where
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 2 100.00 Using filesort
2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 3 100.00 Using where
Warnings:
Note 1276 Field or reference 'test.t2.a' of SELECT #2 was resolved in SELECT #1
Note 1276 Field or reference 'test.t2.a' of SELECT #2 was resolved in SELECT #1
