在sql server中实现查找一个月中有多少星期天

declare @yr int
declare @mth int
declare @from_date datetime
declare @to_date datetime

set @yr='2014' set @mth='11'

--set @from_date=@yr+'-'+@mth+'-1'
set @from_date=ltrim(@yr)+'-'+ltrim(@mth)+'-1'
set @to_date=dateadd(month,1,@from_date)-1

declare @sun int
set @sun=0
while @from_date<@to_date
begin
if(DATEPART(WEEKDAY,@from_date)=1) --判断当天是否是星期日
set @sun=@sun+1
set @from_date=@from_date+1
end

select @sun