删除除前20位的所有旧行

Question

我想从“idx_links”表中删除除最新的20个之外的所有旧行。 pubDate是时间戳。

这个选择带来的行：

SELECT @row := @row + 1 AS row, t.* 
FROM idx_links t, (SELECT @row := 0) r 
having(row>20) 
ORDER BY pubDate DESC 

如何删除此行？

Answer 1

这个怎么样 - 删除pubDate排名前20的所有行。

DELETE idx_links 
WHERE ID NOT IN (SELECT ID FROM idx_links 
        ORDER BY pubDate DESC LIMIT 0,20); 

交替日期，避免子查询的IN条款：

DELETE idx_links 
WHERE pubDate < (SELECT pubDate FROM idx_links 
       ORDER BY pubDate DESC LIMIT 20,1);