Question

我有以下两个表

CREATE TABLE message_log
(
  id integer,
  message text,
  from_id character varying(500),
  to_id character varying(500),
  match_id character varying(500),
  own_account boolean,
  reply_batch boolean DEFAULT false,
  insert_time timestamp with time zone DEFAULT now()
)


CREATE TABLE likes
(
  id integer,
  userid character varying(500),
  insert_time timestamp with time zone DEFAULT now()
)

如果没有发送包含“@”的相同match_id的邮件，我有以下查询返回match_ids。

select distinct(match_id) from message_log where own_account = TRUE and match_id not in 
(select match_id from message_log where message like '%@%')

我还要返回to_ids，因为在我想构建的查询中需要它们，所以我将查询修改为

select distinct(match_id, to_id) from message_log where own_account = TRUE and match_id not in 
(select match_id from message_log where message like '%@%')

现在我想创建一个查询，如果从上面的查询返回的to_id与likes表中的userid匹配，则会删除likes表中的任何行。是否可以在一个查询中执行此操作？

Answer 1

这样的事情应该有效：

delete from b
from (
    select distinct match_id, to_id
    from message_log
    where own_account = TRUE and match_id not in (select match_id from message_log where message like '%@%')
) a inner join likes b on a.to_id = b.userid

基本上，只需将你的结果和内部联接放在你喜欢的表上，以确定从喜欢的表中删除哪些结果。

仅当行被另一个查询返回时才删除行

1 个答案: