如何让 CAST 与除法一起正常工作

Question

我正在使用 SSMS 2014。

我的示例代码如下：

select name
      ,family
      ,group
      ,mcount
      ,icount
      ,(cast(icount as demical(10,2)) / cast(mcount as decimal(10,2))) as per_unit 
from ( select distinct 
           mc.name
          ,mc.family
          ,mc.group
          ,sum(mc.mcount) over (partition by mc.name) as mcount
          ,sum(ic.icount) over (partition by ic.name) as icount
      from mc
      join ic
         on ic.num1 = mc.num1) as a
order by mcount desc

我的每单位列的第一条记录应该除以 76 / 50。这应该 = 1.52，但是，它 returns 1.5200000000000。第二条记录除以 52/28 和 returns 1.8571428571428.

我正在寻找小数点后两位。我读到 cast as decimal(10,2) 但这似乎不起作用。

我做错了什么？？谢谢

Answer 1

你必须对除法的结果进行投射。

改变这个

(cast(icount as demical(10,2)) / cast(mcount as decimal(10,2))) as per_unit

至此

cast(icount  / mcount  as decimal(10,2)) as per_unit

如果 icount 和 mcount 是整数，则保留现有的转换。

Answer 2

将您的部门更改为：

cast((cast(icount as demical(10,2)) / cast(mcount as decimal(10,2))) as decimal(10,2)) as per_unit

或者理想情况下，假设您的 icount 和 mcount 也是 decimal 值：

cast(icount / mcount as decimal(10,2)) as per_unit

Answer 3

再投一次就能得到想要的结果

 cast((cast(icount as demical(10,2)) / cast(mcount as decimal(10,2))) as Decimal(10,2)) per_unit

如何让 CAST 与除法一起正常工作

How to get CAST working correctly with division

sql

tsql

ssms

window-functions