Re: Optimizing GROUP BY

[rihad rihad]

A biggest surprise...

Quote

mysql> EXPLAIN SELECT SUM(uid) FROM logs WHERE uid=206 GROUP BY uid ORDER BY NULL;
+----+-------------+----------+------+---------------+------+---------+-------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+----------+------+---------------+------+---------+-------+------+-------------+
| 1 | SIMPLE | ipn_log | ref | uid | uid | 4 | const | 612 | Using index |
+----+-------------+----------+------+---------------+------+---------+-------+------+-------------+
1 row in set (0.00 sec)

Taking away the quotes from the constant '206' solved the problem... Now there's no type conversion taking place so index magic works. But... doesn't MySQL parser recognize that '206' is a numerical constant and treat it respectively? I always thought I should quote my literals just in case. Very embarrassing on my part....