SQL数据库中查询中加N'' 前缀是什么意思

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于 2017-12-13 16:53:00 发布

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原文链接：http://www.cnblogs.com/qixue/p/8033772.html

本文解释了在Transact-SQL中使用N前缀声明字符串的原因。N前缀表明字符串为Unicode格式，即NCHAR、NVARCHAR或NTEXT类型，而非普通的CHAR、VARCHAR或TEXT类型。当未使用N前缀时，字符串将转换为数据库默认的代码页，这可能导致某些字符无法被正确识别。

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It's declaring the string as nvarchar data type, rather than varchar

You may have seen Transact-SQL code that passes strings around using an N prefix. This denotes that the subsequent string is in Unicode (the N actually stands for National language character set). Which means that you are passing an NCHAR, NVARCHAR or NTEXT value, as opposed to CHAR, VARCHAR or TEXT.

To quote from Microsoft:

Prefix Unicode character string constants with the letter N. Without the N prefix, the string is converted to the default code page of the database. This default code page may not recognize certain characters.

转载于:https://www.cnblogs.com/qixue/p/8033772.html