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。

使用NULLIF(exp,0)，但以这种方式- NULLIF(ISNULL(exp,0)，0)

如果exp为空，NULLIF(exp,0)将中断，但NULLIF(ISNULL(exp,0)，0)将不会中断

在这种情况下，你可以除以0。商业规则是计算库存周转，你用一段时间内的销售成本，按年计算。在你得到年化数字之后，你要除以该时期的平均库存。

I'm looking at calculating the number of inventory turns that occur in a three month period. I have calculated that I have Cost of Goods sold during the three month period of $1,000. The annual rate of sales is $4,000 ($1,000/3)*12. The beginning inventory is 0. The ending inventory is 0. My average inventory is now 0. I have sales of $4000 per year, and no inventory. This yields an infinite number of turns. This means that all my inventory is being converted and purchased by customers.

这是关于如何计算库存周转的业务规则。

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。

用零代替“除零”是有争议的，但这也不是唯一的选择。在某些情况下，用1代替是(合理的)合适的。我经常发现自己吸毒

 ISNULL(Numerator/NULLIF(Divisor,0),1)

当我在看分数/计数的变化，并希望默认为1，如果我没有数据。例如

NewScore = OldScore *  ISNULL(NewSampleScore/NULLIF(OldSampleScore,0),1) 

通常情况下，我实际上在其他地方计算过这个比率(尤其是因为它可以为低分母提供一些非常大的调整因素)。在这种情况下，我通常控制OldSampleScore大于阈值;这就排除了零的可能性。但有时“hack”是合适的。

当错误传播回调用程序时，可以适当地处理它(如果需要，可以忽略它)。在c#中，SQL中发生的任何错误都会抛出一个异常，我可以捕获并在我的代码中处理，就像任何其他错误一样。

I agree with Beska in that you do not want to hide the error. You may not be dealing with a nuclear reactor but hiding errors in general is bad programming practice. This is one of the reasons most modern programming languages implement structured exception handling to decouple the actual return value with an error / status code. This is especially true when you are doing math. The biggest problem is that you cannot distinguish between a correctly computed 0 being returned or a 0 as the result of an error. Instead any value returned is the computed value and if anything goes wrong an exception is thrown. This will of course differ depending on how you are accessing the database and what language you are using but you should always be able to get an error message that you can deal with.

try
{
    Database.ComputePercentage();
}
catch (SqlException e)
{
    // now you can handle the exception or at least log that the exception was thrown if you choose not to handle it
    // Exception Details: System.Data.SqlClient.SqlException: Divide by zero error encountered.
}