我有这样的桌子+-----------+--------------++-----------+--------------++-----------+--------------++-------------+---------------++-------------+---------------+
| 1 | Politic
我想知道会话变量如何使用IN子句使用MySQL。SET @concat_var := (SELECT GROUP_CONCAT(player_id) FROM tableB where id = 1);SELECT player_id FROM tableA WHERE player_id IN (@concat_var);
查询
mysql_query("UPDATE users SET friends = CONCAT(friends,"$friend_id") WHERE username = '$user_logged_in'") or die mysql_error());mysql_query("UPDATE users SET friends = friends +" . ", " .