sql - 如何修改 SQL 查询以迭代每 100 个结果，然后执行外部查询？

Question

以下查询：

DELETE FROM attachmentdata
WHERE attachmentid IN
  ( SELECT attachmentid
    FROM attachments
    WHERE pageid IN
      ( SELECT contentid FROM content_delete )
  );

如果内部嵌套的 SELECT 查询返回一个小列表（可能是几百个），则可以完美地工作。

但现在我试图在将返回 10000 - 15000 行的东西上运行它，这需要很长时间。我运行了查询，45 分钟后没有任何反应。

是否可以修改查询，以便内部 SELECT 返回的每 100 个结果都转到外部 DELETE 查询，然后转到下一个 100 个结果？

Answer 1

为了让它更快，摆脱IN...

（甲骨文）...

DELETE  ad
FROM attachmentdata AS ad 
INNER JOIN attachments AS att ON ad.attachmentid = att.attachmentid
INNER JOIN content_delete AS cd ON cd.contentid = att.pageid

(mysql) ...

DELETE  ad.*
FROM attachmentdata AS ad 
INNER JOIN attachments AS att ON ad.attachmentid = att.attachmentid
INNER JOIN content_delete AS cd ON cd.contentid = att.pageid