连续三周查找订单

Question

我有下面的表格，该表格在2018年和2019年的两年中有重叠的几周。我想为每个使用TSQL的客户确定连续3周的第一套。

结果集应该具有连续3周的第一组的customer_id和max（order_date），如下所示。

Answer 1

我创建了自己的数据。尝试运行此命令（这使用了2012年及以后的功能的窗口功能）：

 create table i1(i1 int identity (1,1) primary key, idate date, name varchar(25));
 insert into i1 values ('1-1-2019','b'),  ('1-8-2019','b'), ('1-15-2019','b'),
 ('1-1-2019','c'),  ('1-8-2019','c'), ('1-24-2019','c'),('1-31-2019','c')

 ;
 with ct1 as (select name,idate, datepart(ww,idate) -lag(datepart(ww,idate),1,0)  over (partition by name order by idate) diff
    ,row_number() over (partition by name order by idate) id from i1),
          ct2 as (
   select name ,  idate,sum(diff) over ( partition by name order by idate rows between  3 preceding and current row) diff2 
     from ct1)



select   name, idate
   from ct2 where diff2=3