如何使用单个查询更新两行的交换值

Question

是否有查询可以用单个查询交换两行的值？

Answer 1

您可以在本文中看到解决方案

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

查看：优雅的方式，进行连接以获取2行中的数据，将其换成1行，之后进行更新很容易。

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
;

Answer 2

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