如何使用单个查询更新两行的交换值 [英] how to update swap values of two rows with single query

问题描述

是否有一个查询，我可以通过一次查询交换两行的值?

Is there a query with which i can exchange the values of two rows with single query?

推荐答案

您可以在本文中看到解决方案

you can see the solution in this article

http://www.microshell.com /database/sql/swap-values-in-2-rows-sql/

查看:一种优雅的方式，进行联接以从2行中获取数据，然后将其交换为1行，然后进行更新就很容易了.

look at the : The elegant way , make a join to get the data from the 2 rows to be swapped in 1 row, after that make an update is easy.

示例:

UPDATE
rules AS rule1
JOIN rules AS rule2 ON
( rule1.rule_id = 1 AND rule2.rule_id = 4 )
SET
rule1.priority = rule2.priority,
rule2.priority = rule1.priority
;

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