下面两段代码,SUM 的结果是正确的,COUNT 的结果就是错误的,请大神指点,难道是 COUNT 与 IIF 配合查询有错?
SELECT
COUNT(iif(产品分类='A',产品编号,0)) as A产品
,COUNT(iif(产品分类='B',产品编号,0)) as B产品
,COUNT(iif(产品分类='C',产品编号,0)) as C产品
FROM 产品清单
SELECT
SUM(iif(产品分类='A',销售额,0)) as A产品
,SUM(iif(产品分类='B',销售额,0)) as B产品
,SUM(iif(产品分类='C',销售额,0)) as C产品
FROM 产品销售表