解决mysql查询问题 [英] solve mysql query problem

问题描述

CONCAT(MONTHNAME(i.time), ' ', YEAR(i.time), c.categoryName) 

错误代码：1271。操作'concat'的非法混合排序

Error Code: 1271. Illegal mix of collations for operation 'concat'

推荐答案

请参阅：



http：//www.experts -exchange.com/Programming/Languages/Scripting/PHP/Q_26634253.html [ ^ ]

请查看eggyal发布的答案：http://stackoverflow.com/questions/3029321/troubleshooting-illegal-mix-of-collat​​ions-error-in-mysql [ ^ ]



据我所知，你不能混合使用数字和字符串值。您需要将其转换/转换为字符串

Please, see the answer posted by eggyal: http://stackoverflow.com/questions/3029321/troubleshooting-illegal-mix-of-collations-error-in-mysql[^]

As per i understand you can't mix numeric and string values. You need to convert/cast it to string

SELECT CONCAT(MONTHNAME(i.time), ' ', CONVERT(CHAR(4), YEAR(i.time)), c.categoryName) AS NewColName
FROM ...

另一个原因是每个表的排序规则不同。您可以使用 CONVERT 函数来解决它。

Another reason is different collation for each table. You can workaround it by using CONVERT function.

SELECT CONVERT(c.categoryName USING utf8) AS Utf8CategoryName

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