Mysql用SELECT CASE的结果存储变量 [英] Mysql Storing a variable with the result of an SELECT CASE

问题描述

我正在学习如何使用SELECT CASE，但我不太了解，这是代码:

im learning how to use the SELECT CASE but i don't understand very well, here is the code:

SET @vgls=1;
SET @lgls=1;


SET @st=SELECT CASE 
WHEN @vgls=@lgls THEN "emp"
WHEN @vgls>@lgls THEN "loc"
WHEN @vgls<@lgls THEN "vis" END;

SELECT @st;

它给了我以下错误:

[Err] 1064 - You have an error in your SQL syntax; check the manual that corresponds to you  MySQL server version for the right syntax to use near 'SELECT CASE 
WHEN @vgls=@lgls THEN "emp"
WHEN @vgls>@lgls THEN "loc"
WHEN @vg' at line 1

推荐答案

您需要使用 SELECT ... INTO

You need to use SELECT ... INTO

SELECT
...
INTO var_name [, var_name]]

使用

而不是set将SELECT的结果分配给变量.因此，应该这样做:

instead of set to assign the result of a SELECT to a variable. So this should do it:

SELECT CASE 
WHEN @vgls=@lgls THEN "emp"
WHEN @vgls>@lgls THEN "loc"
WHEN @vgls<@lgls THEN "vis" END
INTO @st;

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