刪除除前20位的所有舊行

Question

我想從「idx_links」表中刪除除最新的20個之外的所有舊行。 pubDate是時間戳。

這個選擇帶來的行：

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

如何刪除此行？

Answer 1

這個怎麼樣 - 刪除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，避免子查詢的IN條款：

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