User:
Title: exp
Content:
mysql> mysql> EXPLAIN SELECT regat_uid as user_id, user_name, SUM(regat_score) AS user_level, GROUP_CONCAT(regat_sid) AS site_ids, GROUP_CONCAT(regat_solved) AS site_solveds, COUNT(regat_score) AS nlinks, user_countryid FROM wc4_wc_regat AS B JOIN wc4_wc_site AS S ON B.regat_sid = S.site_id JOIN wc4_user AS U ON B.reg= U.user_id WHERE site_status = 'up' GROUP by regat_uid ORDER BY user_level DESC, user_id ASC LIMIT 0, 50;
+----+-------------+-------+--------+-----------------------------+-------------+---------+----------------------+------+--------------------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+--------+-----------------------------+-------------+---------+----------------------+------+--------------------------------------------------------+
| 1 | SIMPLE | S | ref | PRIMARY,site_status | site_status | 2 | const | 56 | Using index condition; Using temporary; Using filesort |
| 1 | SIMPLE | B | ref | PRIMARY,regat_sid,regat_uid | regat_sid | 4 | wechall5.S.site_id | 874 | NULL |
| 1 | SIMPLE | U | eq_ref | PRIMARY | PRIMARY | 4 | wechall5.B.regat_uid | 1 | NULL |
+----+-------------+-------+--------+-----------------------------+-------------+---------+----------------------+------+--------------------------------------------------------+
3 rows in set (0,00 sec)