具有重复日期的前导窗口功能

Question

此处的示例数据：http :
//rextester.com/VNGMF66717

我有以下数据：

  ID    Year    Date    
1111    2016    2016-02-28
1111    2016    2016-02-28
1111    2016    2016-03-31
1111    2016    2016-03-31
1111    2016    2016-03-31
1111    2016    2016-04-02
1111    2016    2016-05-31
1111    2016    2016-08-01
1111    2016    2016-12-11
1111    2017    2017-01-02
1111    2017    2017-01-02
1111    2017    2017-02-04
1111    2017    2017-02-04
1111    2017    2017-07-08
2222    2016    2016-02-11
2222    2016    2016-02-11
2222    2016    2016-03-28
2222    2016    2016-03-28
2222    2016    2016-03-28
2222    2016    2016-07-22
2222    2016    2016-12-31
2222    2017    2017-02-01
2222    2017    2017-02-14

我想直接在SELECT语句中使用线索窗口函数添加NextDate列（在每个ID和年份内重置），而不是像提供的示例中那样使用RANK 窗口函数进行自我联接。

NextDate列应完全像这样

  ID    Year    Date        NextDate
1111    2016    2016-02-28  2016-03-31
1111    2016    2016-02-28  2016-03-31
1111    2016    2016-03-31  2016-04-02
1111    2016    2016-03-31  2016-04-02
1111    2016    2016-03-31  2016-04-02
1111    2016    2016-04-02  2016-05-31
1111    2016    2016-05-31  2016-08-01
1111    2016    2016-08-01  2016-12-11
1111    2016    2016-12-11  NULL
1111    2017    2017-01-02  2017-02-04
1111    2017    2017-01-02  2017-02-04
1111    2017    2017-02-04  2017-07-08
1111    2017    2017-02-04  2017-07-08
1111    2017    2017-07-08  NULL
2222    2016    2016-02-11  2016-03-28
2222    2016    2016-02-11  2016-03-28
2222    2016    2016-03-28  2016-07-22
2222    2016    2016-03-28  2016-07-22
2222    2016    2016-03-28  2016-07-22
2222    2016    2016-07-22  2016-12-31
2222    2016    2016-12-31  NULL
2222    2017    2017-02-01  2017-02-14
2222    2017    2017-02-14  NULL

有人知道如何正确执行此操作吗？

Answer 1

这可能不完全是您的意思，但是通过使用两个带有嵌套选择的窗口函数：MAX(LEAD)，您可以获得所需的结果。

select
    id, yr, dt
    ,MAX(nx_dt) OVER (PARTITION BY id, dt) nxt_dt
FROM
    (
        select 
            *
            , LEAD(dt) OVER (PARTITION BY id, yr ORDER BY id, yr, dt) nx_dt
        from
        #testtable
    ) sub

/*
drop table #testtable

create table #testtable
(
    id int, yr int, dt date
)
insert into #testtable
(
    id, yr, dt
)
SELECT 1111,2016,'2016-02-28'   union all
SELECT 1111,2016,'2016-02-28'   union all
SELECT 1111,2016,'2016-03-31'   union all
SELECT 1111,2016,'2016-03-31'   union all
SELECT 1111,2016,'2016-03-31'   union all
SELECT 1111,2016,'2016-04-02'   union all
SELECT 1111,2016,'2016-05-31'   union all
SELECT 1111,2016,'2016-08-01'   union all
SELECT 1111,2016,'2016-12-11'   union all
SELECT 1111,2017,'2017-01-02'   union all
SELECT 1111,2017,'2017-01-02'   union all
SELECT 1111,2017,'2017-02-04'   union all
SELECT 1111,2017,'2017-02-04'   union all
SELECT 1111,2017,'2017-07-08'   union all
SELECT 2222,2016,'2016-02-11'   union all
SELECT 2222,2016,'2016-02-11'   union all
SELECT 2222,2016,'2016-03-28'   union all
SELECT 2222,2016,'2016-03-28'   union all
SELECT 2222,2016,'2016-03-28'   union all
SELECT 2222,2016,'2016-07-22'   union all
SELECT 2222,2016,'2016-12-31'   union all
SELECT 2222,2017,'2017-02-01'   union all
SELECT 2222,2017,'2017-02-14'
*/