where 
datediff(qq,'2007-03-01',getdate())=0--本季度
datediff(qq,'2007-03-01',getdate())=1--上季度
datediff(qq,'2007-03-01',getdate())=2--上上季度
datediff(mm,'2007-03-01',getdate())=0--本月
datediff(mm,'2007-03-01',getdate())=1--上月
datediff(mm,'2007-03-01',getdate())=2--上上月
datediff(ww,'2007-03-01',getdate())=0--本周
datediff(ww,'2007-03-01',getdate())=1--上周
datediff(ww,'2007-03-01',getdate())=2--上上周
datediff(dd,'2007-03-01',getdate())=0--今天
datediff(dd,'2007-03-01',getdate())=1--昨天
datediff(dd,'2007-03-01',getdate())=2--前天