新手求助

前几个？还是说只要是星期一都要统计就对了？

select avg(销售额) 平均销售额 from 表 where 日期 in(
dateadd(wk, datediff(wk,0,getdate()), 0)
,dateadd(wk, datediff(wk,0,getdate()), 0) -7
,dateadd(wk, datediff(wk,0,getdate()), 0) -7*2
,dateadd(wk, datediff(wk,0,getdate()), 0) -7*3
,dateadd(wk, datediff(wk,0,getdate()), 0) -7*4
)