我有这个错误信息:

Msg 8134,级别16,状态1,第1行,除以零错误。

写SQL代码的最好方法是什么,这样我就再也不会看到这个错误消息了?

我可以做以下任何一件事:

添加where子句,使除数永远不为零

Or

我可以添加一个case语句,这样就可以对0进行特殊处理。

使用NULLIF子句是最好的方法吗?

有没有更好的办法,或者如何实施?


当前回答

CREATE FUNCTION dbo.Divide(@Numerator Real, @Denominator Real)
RETURNS Real AS
/*
Purpose:      Handle Division by Zero errors
Description:  User Defined Scalar Function
Parameter(s): @Numerator and @Denominator

Test it:

SELECT 'Numerator = 0' Division, dbo.fn_CORP_Divide(0,16) Results
UNION ALL
SELECT 'Denominator = 0', dbo.fn_CORP_Divide(16,0)
UNION ALL
SELECT 'Numerator is NULL', dbo.fn_CORP_Divide(NULL,16)
UNION ALL
SELECT 'Denominator is NULL', dbo.fn_CORP_Divide(16,NULL)
UNION ALL
SELECT 'Numerator & Denominator is NULL', dbo.fn_CORP_Divide(NULL,NULL)
UNION ALL
SELECT 'Numerator & Denominator = 0', dbo.fn_CORP_Divide(0,0)
UNION ALL
SELECT '16 / 4', dbo.fn_CORP_Divide(16,4)
UNION ALL
SELECT '16 / 3', dbo.fn_CORP_Divide(16,3)

*/
BEGIN
    RETURN
        CASE WHEN @Denominator = 0 THEN
            NULL
        ELSE
            @Numerator / @Denominator
        END
END
GO

其他回答

为了避免“除零”错误,我们编写了这样的程序:

Select Case when divisor=0 then null
Else dividend / divisor
End ,,,

但这里有一种更好的方式:

Select dividend / NULLIF(divisor, 0) ...

现在唯一的问题是记住NullIf位,如果我使用“/”键。

There is no magic global setting 'turn division by 0 exceptions off'. The operation has to to throw, since the mathematical meaning of x/0 is different from the NULL meaning, so it cannot return NULL. I assume you are taking care of the obvious and your queries have conditions that should eliminate the records with the 0 divisor and never evaluate the division. The usual 'gotcha' is than most developers expect SQL to behave like procedural languages and offer logical operator short-circuit, but it does NOT. I recommend you read this article: http://www.sqlmag.com/Articles/ArticleID/9148/pg/2/2.html

添加一个CHECK约束,强制除数为非零 向表单添加验证器,以便用户不能在该字段中输入零值。

SELECT Dividend / ISNULL(NULLIF(Divisor,0), 1) AS Result from table

通过使用nullif()捕获零,然后使用isnull()捕获结果为零,可以避免除零错误。

你至少可以阻止查询被错误打断,如果有被0除,返回NULL:

SELECT a / NULLIF(b, 0) FROM t 

然而,我永远不会像其他得到很多赞的答案那样,用合并将其转换为零。从数学意义上讲,这是完全错误的,甚至是危险的,因为您的应用程序可能会返回错误和误导性的结果。