如何使用单个查询更新两行的交换值

Question

是否有一个查询可以用单个查询交换两行的值？

Answer 1

您可以在本文中查看解决方案

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

看一下：优雅的方式，进行连接以从2 行交换为 1 行，之后更新很容易。

例子 ：

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
;

Answer 2

UPDATE my_table SET a=@tmp:=a, a=b, b=@tmp;