从子查询中删除

Question

我的查询无效：

DELETE FROM (
     SELECT *
     FROM `chat`
     ORDER BY `message_id` ASC
     LIMIT 50
) AS deleted

Answer 1

不要使用子查询：

DELETE c FROM `chat` c
    ORDER BY `message_id` ASC
    LIMIT $NUM;

在MySQL中，DELETE支持order by和limit。

Answer 2

$sql3 = "DELETE FROM chat ORDER BY message_id LIMIT ".$NUM;