MySQL: ORDER BY column DESC LIMIT (SELECT COUNT(*) FROM table);

【问题标题】：MySQL: ORDER BY column DESC LIMIT (SELECT COUNT(*) FROM table);MySQL: ORDER BY column DESC LIMIT (SELECT COUNT(*) FROM table);
【发布时间】：2020-03-25 19:49:20
【问题描述】：

如果这个问题很愚蠢，我深表歉意。代码很容易理解。

语法错误出现在最后一行。我该如何克服它？

    SELECT id
    FROM m_users
    ORDER BY id DESC
    LIMIT (SELECT COUNT(*) FROM tmp_students);

【问题讨论】：

标签： mysql sql database

【解决方案1】：

你可以使用窗口函数：

SELECT u.id
FROM (SELECT u.*, ROW_NUMBER() OVER (ORDER BY id DESC) as seqnum
      FROM m_users u
     ) u
WHERE seqnum <= (SELECT COUNT(*) FROM tmp_students)
ORDER BY id DESC

【讨论】：

@user8555937 。 . . LIMIT 在 MySQL 中需要一个常量。