T-SQL 中是否有异或运算符? [英] Is there an exclusive OR operator in T-SQL?

问题描述

这是我的声明

IF (@UserName IS NULL AND @EditorKey IS NULL) OR (@UserName IS NOT NULL AND @EditorKey IS NOT NULL) BEGIN
    RAISERROR ('One of @UserName, @EditorKey must be non-null.', 15, 0)
    RETURN
END

我想要的是能够做这样的事情:

What I want is to be able to do something like this:

IF (@UserName IS NOT NULL) XOR (@EditorKey IS NOT NULL) BEGIN
    RAISERROR ('One of @UserName, @EditorKey must be non-null.', 15, 0)
    RETURN
END

对于两个参数来说，这没什么大不了的，但有些 procs 有三个或四个，其中只有一个可以传递，其余的应该为空.

For two parameters it isn't that big of a deal, but some procs have three or four where in only one may be passed and the rest should be null.

推荐答案

不是很简洁，但你可以像这样展开逻辑:

Not very succinct, but you could expand out the logic like this:

WHERE
    (NOT ((@UserName IS NOT NULL) AND (@EditorKey IS NOT NULL))) AND
    ((@UserName IS NOT NULL) OR (@EditorKey IS NOT NULL))

或者使用按位异或运算符(^):

Or use the bitwise XOR operator (^):

WHERE
    (CASE WHEN (@UserName IS NOT NULL) THEN 1 ELSE 0 END) ^
    (CASE WHEN (@EditorKey IS NOT NULL) THEN 1 ELSE 0 END) = 1

您可以使用类似的方法，其中有三个或四个参数，并且只有一个必须有值:

You can use a similar approach where there are three or four parameters, and exactly one must have a value:

WHERE
    (CASE WHEN (@Var1 IS NOT NULL) THEN 1 ELSE 0 END) +
    (CASE WHEN (@Var2 IS NOT NULL) THEN 1 ELSE 0 END) +
    (CASE WHEN (@Var3 IS NOT NULL) THEN 1 ELSE 0 END) +
    (CASE WHEN (@Var4 IS NOT NULL) THEN 1 ELSE 0 END) = 1

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