MS sqlserver 获取某月某年的天数

 --定义传入时间
 declare @datetime varchar(10)
 set @datetime='2012-02-01'
 --定义月的天数
 declare @dayCountM int
 --定义年的天数
 declare @dayCountY int
 select @dayCountY=datediff(day,(cast ((datepart(year,dateadd(year,-1,@datetime))) as varchar)+'-12-31'),((cast (datepart(year ,@datetime) as varchar))+'-12-31'))
 select @dayCountM=datediff(day,(cast(datepart(year,@datetime) as varchar)+'-'+cast(datepart(month,@datetime) as varchar)+'-1'),(cast(datepart(year,dateadd(month,1,@datetime)) as varchar)+'-'+cast(datepart(month,dateadd(month,1,@datetime)) as varchar)+'-1'))
 
 select @dayCountM as dayCountM,@dayCountY as dayCountY