我有以下T-SQL查询：
select
count(CaseId),(SELECT DATEDIFF(day,CreateDate,LastActivityDate)) AS DiffDate
from
VW_Case_Analysis
where
CaseStatus = 'C'
and LastActivityDate between '2013-4-1 00:00:00.000' and '2013-4-30 23:59:59.000'
Group By
DiffDate
我收到以下错误：
Msg 207,Level 16,State 1,Line 15
Invalid column name ‘DiffDate’.
例：
天
1 = 3例
2 = 50例
3 = 20例
我该怎么做到这一点？
解决方法
您需要在GROUP BY子句中使用整个表达式,或者只是将整个语句包装在子查询中,并对外部语句进行分组.
您不能在SELECT语句的同一级别上创建的GROUP BY子句上使用ALIAS的原因是因为GROUP BY在创建ALIAS的SELECT子句之前执行.
这是sql操作顺序：
> FROM子句
> WHERE子句
> GROUP BY子句
> HAVING子句
> SELECT子句
> ORDER BY子句
试试这个查询,
SELECT COUNT(CaseId),DiffDate
FROM
(
select CaseId,DATEDIFF(day,LastActivityDate) AS DiffDate
from VW_Case_Analysis
where CaseStatus = 'C' and
LastActivityDate between '2013-4-1 00:00:00.000' and '2013-4-30 23:59:59.000'
) sub
Group By DiffDate
