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

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

其他回答

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

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。

有时,0可能不合适,但有时1也不合适。有时,从0到100,000,000的跳跃被描述为1%或100%的变化也可能是误导性的。在这种情况下,100,000,000 %可能是合适的。这取决于你打算根据百分比或比率得出什么样的结论。

例如,一个非常小的销售项目从2-4个销量变化,而一个非常大的销售项目从1,000,000个销量变化到2,000,000个销量变化,对分析师或管理层来说可能意味着非常不同的东西,但都是100%或1个变化。

隔离NULL值可能比在一堆混合了合法数据的0%或100%行中搜索要容易得多。通常,分母中的0可能表示错误或缺少值,您可能不想只是为了使数据集看起来整洁而填充任意值。

CASE
     WHEN [Denominator] = 0
     THEN NULL --or any value or sub case
     ELSE [Numerator]/[Denominator]
END as DivisionProblem

使用where子句过滤数据,这样就不会得到0值。

如果你想返回零,如果发生零分割,你可以使用:

SELECT COALESCE(dividend / NULLIF(divisor,0), 0) FROM sometable

对于每一个为0的除数,结果集中都会得到一个0。