在mysql中，删除后可以返回删除的行吗? [英] In mysql can I return deleted rows after a deletion?

问题描述

如何在mysql中返回以下查询的已删除记录?

How to return deleted records of following query in mysql?

DELETE t1
FROM t1
LEFT JOIN t2 on (t1.t2_id = t2.id)
WHERE t2.id IS NULL OR t2.is_valid = false

背景:

$ mysql --version
mysql  Ver 14.14 Distrib 5.6.23, for osx10.8 (x86_64) using  EditLine wrapper

推荐答案

MySQL不具有output或

MySQL doesn't have the equivalent of the output or returning clauses provided by other databases. Your best bet is a temporary table:

CREATE TABLE TheDeletedIds as
    SELECT t1.id
    FROM t1 LEFT JOIN
         t2 
         ON t1.t2_id = t2.id
    WHERE t2.id IS NULL OR t2.is_valid = false;

DELETE t1
    FROM t1
    WHERE t1.id IN (SELECT id FROM TheDeletedIds);

然后，您刚刚创建的表具有所需的ID.

Then the table you just created has the ids you want.

注意:使用新创建的表进行删除很重要.否则，另一个线程/进程可能会在捕获ID的时间和删除ID的时间之间更改数据.

Note: It is important to use the newly-created table for the deletion. Otherwise, another thread/process could change the data between the time you capture the ids and the time you delete them.

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