为什么在MySQL中使用CAST时会出现语法错误? [英] Why do I get a syntax error when using CAST in MySQL?

问题描述

我正在使用MySQL Workbench v5.2.44 CE.我正在针对本地MySQL 5.5安装运行它.

I am using MySQL workbench v5.2.44 CE. I am running it against a local MySQL 5.5 install.

我正在尝试使用CAST函数，但始终出现以下错误:

I am trying to use the CAST function, but keep getting the following error:

语法错误，意外的INT_SYM

syntax error, unexpected INT_SYM

什么是源日期类型和目标日期类型都没有关系.只有当目标数据类型为DECIMAL时，它才不会出现错误.这是一个示例:

It doesn't matter what the source and target date types are. The only time it doesn't give me an error is when the target datatype is DECIMAL. Here is an example:

SELECT CAST(IFNULL(comboCount, 1) * COUNT(partID) AS INT) INTO comboCount
FROM productOption

我已经尝试了一切，但似乎没有任何效果.

I have tried everything, but nothing seems to work.

推荐答案

尝试在外部进行数学运算:

Try to do the math outside:

SELECT CAST(IFNULL(comboCount, 1) AS INT) * COUNT(partID) INTO comboCount
FROM productOption

如果这不起作用，请尝试将CAST设置为UNSIGNED；不是INT.

If that doesn't work, try to CAST as UNSIGNED; not INT.

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