本周数据：select * from Keywords where datediff(week, Addtime,getdate())=0
本月：select * from Keywords where datediff(month, Addtime,getdate())=0
本季度：select * from Keywords where datediff(quarter, Addtime,getdate())=0
本年：select * from Keywords where datediff(year, Addtime,getdate())=0
