在MySQL的`IN()`中使用逗号分隔的字符串 [英] Use a comma-separated string in an `IN ()` in MySQL

问题描述

如果用户定义的变量@x是由逗号分隔的数字组成的字符串，例如'1,2,4'，是否可以在IN ()函数中使用它?

If a user-defined variable @x is a string of comma separated numbers, e.g. '1,2,4', is there a way to use it in an IN () function?

特别是:

SET @x := '1,2,4';
SELECT * FROM t WHERE c IN (@x);

不选择t等于c等于1或2或4的行.

does not select rows in t where c equals 1 or 2 or 4.

推荐答案

您不能直接使用变量来执行此操作.根据您现在拥有的内容，服务器正在尝试执行select * form t where c in ('1,2,3'); ...显然，鉴于要检查c是否包含给定的单个字符串，这显然不是您想要的.

You can't do this directly using a variable. Based on what you have now, the server is trying to execute select * form t where c in ('1,2,3'); ... which clearly isn't what you want given that you're checking to see if c contains the single string given.

您必须根据列表生成动态SQL，以使其正常工作.

You must generate dynamic SQL based off of your list in order to get this to work.

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