sql - 删除mysql中的最后n行

Question

我正在尝试删除给定表中的最后 N 行。我尝试运行以下脚本

DELETE FROM SCHEMA ORDER BY PID DESC LIMIT 26000;

但是我收到了这个错误

Message: [SQL0199] Keyword ORDER not expected. Valid tokens: USE SKIP WAIT WITH WHERE. Cause . . . . . : The keyword ORDER was not expected here.

我也试过运行这个脚本

DELETE FROM SCHEMA WHERE PID IN (SELECT PID FROM (SELECT  PID FROM SCHEMA ORDER BY PID DESC limit 26000) a );

但是，除了关键字不是“LIMIT”之外，我还是遇到了同样的错误。

我的语法有错误吗？对我如何做到这一点有什么建议吗？

Answer 1

您的错误是 DB2 错误，而不是 MySQL 错误。我建议:

DELETE FROM SCHEMA
    WHERE PID IN (SELECT PID
                  FROM SCHEMA
                  ORDER BY PID DESC 
                  FETCH FIRST 26000 ROWS ONLY
                 ) ;

我认为这也行:

DELETE FROM SCHEMA
    ORDER BY PID
    FETCH FIRST 26000 ROWS ONLY;

也许您使用的 DB2 版本不支持 DELETE 中的 ORDER BY。