一个常用sql的日期表达

前30天convert(nvarchar(10),dateadd(day,-30,getdate()),120)

当月月初convert(varchar(10),dateadd(day,0,getdate()-day(getdate()-1)),120)

当月月末convert(varchar(10),dateadd(month,1,getdate()-day(getdate())),120)

其它非时间格式的表达计算

:rk_rq月初近两月

 rq>=convert(datetime,convert(varchar(4),year(:rk_rq))+'-'+convert(varchar(2),month(:rk_rq))+'-'+convert(varchar(2),day(:rk_rq)))-day(:rk_rq)+1

 and rq<convert(datetime,convert(varchar(4),year(:rk_rq))+'-'+convert(varchar(2),month(:rk_rq)+2)+'-'+convert(varchar(2),day(:rk_rq)))-day(:rk_rq)+1