SQL 按月统计（两种方式）

(1)Convert 函数

select Convert ( VARCHAR(7),ComeDate,120) as Date ,Count(In_code) as 单数,Sum(SumTrueNum) as 件数 

from T_In_Top 
where  ComeDate between "2013-01-01" and "2014-08-04" and In_top_State="已完成" and Case_ID=14  and Store_ID=41
group by Convert ( VARCHAR(7),  ComeDate,  120)

(2)日期函数 year([date])

select year(ComeDate),month(ComeDate),Count(In_code) as 单数,Sum(SumTrueNum) as 件数
from  T_In_Top
where Case_ID=14 and In_top_State="已完成" and Store_ID=41 and year(ComeDate)>=2013

group by month(ComeDate),year(ComeDate) 

--(cast(year(ComeDate) as varchar(4))) cast 函数 类型转换