Question

我有简单的SQL：

SELECT Count(c.[id]) 'Count'
      ,Count(c.[phone_home]) 'phone_home '
      ,CAST(Count(c.[phone_home])*100/Count(c.[id]) as  decimal(18,2)) '%'
      ,Count(c.[phone_other]) 'phone_other '
      ,CAST(Count(c.[phone_other])*100.0/Count(c.[id]) as decimal(18,2) ) '%'
      ,Count(c.[primary_address_state]) 'primary_address_state '
      ,CAST(Count(c.[primary_address_state])*100/Count(c.[id]) as DECIMAL(18,2)) '%'
FROM [sugarcrm_cmsru_dev].[dbo].[contacts] c

我注意到百分比的计算不正确。对于这个表达式：

CAST(Count(c.[phone_other])*100.0/Count(c.[id]) as decimal(18,2) ) '%'

结果为0.24

对于这个表达式：

CAST(Count([primary_address_state])*100/Count(c.[id]) as decimal(18,2)) '%'

结果为0,00

但表达方式彼此相同。怎么了？

Answer 1

CAST（计数（c。[phone_other]） * 100.0 /计数（c。[id]）为十进制（18,2））＆＃39;％＆＃39;

CAST（Count（[primary_address_state]） * 100 / Count（c。[id]）为十进制（18,2））＆＃39;％＆＃39;

您的区别在于粗体，您需要将第二个100更改为100.0，SQL将第一个解释为数字，因此将答案作为数字给出，但第二个被解释为整数，因此答案是（舍入的）整数

SQL Server中CAST函数的奇怪工作

1 个答案: