SQL Server 数据类型 nvarchar 和 varchar 不兼容错误
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SQL Server datatypes nvarchar and varchar are incompatible error
提问by Mych
I've inherited a C# app which I've converted to vb. I get one error which as far as I can see has nothing to do with the conversion.
我继承了一个 C# 应用程序，该应用程序已转换为 vb。我收到一个错误，据我所知，该错误与转换无关。
I have a SQL statement which is....
我有一个 SQL 语句，它是....
SELECT ResolverID AS ddlValue, ResolverTeam & ' | ' & ResolverPerson AS ddlText
FROM dbo.TblResolvers
ORDER BY ResolverTeam, ResolverPerson;
When this runs I get the error:
当它运行时，我收到错误：
The data types nvarchar and varchar are incompatible in the boolean AND operator.
数据类型 nvarchar 和 varchar 在布尔 AND 运算符中不兼容。
In the table both ResolverTeamand ResolverPersonare specified as (nvarchar(255), null)
在表中，ResolverTeam和ResolverPerson都指定为 ( nvarchar(255), null)
Why am I getting this error?
为什么我收到这个错误？
回答by Leonardo
Try replacing the &for a +; by the looks of it, what you're trying to do is to concatenate 2 columns. Something you do need to be careful about is that nvarcharis double the size of regular varchar, which means there are chars in nvarcharthat are not in the varchartable.
尝试替换&for a +; 从它的外观来看，您要做的是连接 2 列。您需要注意的是它nvarchar是常规大小的两倍varchar，这意味着其中nvarchar有不在varchar表中的字符。
回答by Mahmoud Gamal
You should use the +for string concatenation:
您应该使用+for 字符串连接：
SELECT
ResolverID AS ddlValue,
ResolverTeam + ' | ' + ResolverPerson AS ddlText
FROM dbo.TblResolvers
Order By ResolverTeam, ResolverPerson;
Why am I getting this error?
为什么我收到这个错误？
You were getting that error, because of the &operator, which is the Bitwise AND.
由于&运算符，您收到了该错误，即按位 AND。
回答by valex
To concatenate strings in MSSQL you should use +
要在 MSSQL 中连接字符串，您应该使用 +
SELECT ResolverID AS ddlValue,
ResolverTeam + ' | ' + ResolverPerson AS ddlText
FROM dbo.TblResolvers Order By ResolverTeam, ResolverPerson;
回答by the_marcelo_r
Is this a concatenation attempt? ResolverTeam & ' | ' & ResolverPerson
这是连接尝试吗？ ResolverTeam & ' | ' & ResolverPerson
&is the bitwise operator AND, replace it with +and see what happens.
&是按位运算符AND，将其替换为+，看看会发生什么。
