Question

我正在检索一些计数，例如按季度分组的“新产品”和“销售数量”。我需要计算这些计数的比率。所以，我的查询是这样的：

select YR, 
       QTR, 
       MAX(#ofsales) AS '# of Sales', 
       MAX(#Totalproducts) AS '# of Total Products',
       MAX(#ofsales*100/#Totalproducts) AS '% of Products Sold',
       MAX(#Totalproducts/#ofsales) AS 'Inventory'
from (union of few tables)
order by YR, QTR
group by YR, QTR;

结果是：

Yr   | Qtr   |# of Sales|# of Total products|% of Products Sold|Inventory
2016 |  1    |   5231   |       7239        |      NULL        |  NULL
2016 |  2    |   3678   |       4752        |      NULL        |  NULL

我正在使用MAX（）运算符，否则，我会收到如下错误：

Column '#ofsales' is invalid in the select list because it is not 
contained in either an aggregate function or the GROUP BY clause

在回答@ mypetlion的问题时，这是我没有MAX（）函数的查询。

select YR, 
       QTR, 
       #ofsales AS '# of Sales', 
       #Totalproducts AS '# of Total Products',
       #ofsales*100/#Totalproducts AS '% of Products Sold',
       MAX(#Totalproducts/#ofsales) AS 'Inventory'
from (union of few tables)
order by YR, QTR
group by YR, QTR;

Answer 1

您可以使用COALESCE函数包装分母。它将检查值是否为NULL并返回您给出的值。由于您试图避免除以零错误，因此可以让它返回1.

select YR, 
       QTR, 
       #ofsales AS '# of Sales', 
       #Totalproducts AS '# of Total Products',
       #ofsales*100/#Totalproducts AS '% of Products Sold',
       MAX(#Totalproducts/COALESCE(#ofsales, 1)) AS 'Inventory'
from (union of few tables)
order by YR, QTR
group by YR, QTR;

Answer 2

由于MAX（）函数，无法找到使分区在原始Query中工作的方法。因此，作为一种解决方法，我将所有结果导入到一个新表中，然后应用了除法，它运行良好。

将1列除以另一列时获取NULL

2 个答案: