sql语法(如果存在) [英] sql syntax, if exist

问题描述

为什么我会出错:

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'IF EXISTS(SELECT id FROM mytable WHERE id = '1')' at line 1 

查询:

IF EXISTS(SELECT id FROM mytable WHERE id = '1')

谢谢

推荐答案

IF EXISTS仅在存储过程中有效.在存储过程之外，IF()是一个带有3个参数的函数.正确的用法是

IF EXISTS only works in a stored procedure. Outside of a stored procedure, IF() is a function which takes 3 arguments. Proper usage would be

SELECT IF(EXISTS(SELECT `column` FROM `table` WHERE `id` = `1`), 1, 0);

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