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sql - 行集总，周期日期

问题描述

我想查看lead类型，如果该类型与该行相同，则合并这些日期以适合一行。

我有下表：

id    start_dt     end_dt    type
 1     1/1/19      2/21/19   cross
 1     2/22/19     6/5/19    cross
 1     6/6/19      8/31/19   cross
 1     9/1/19      10/3/19   AAAA
 1     10/4/19     10/4/19   cross
 1     10/5/19     10/6/19   AAAA
 1     10/7/19     10/10/19  AAAA
 1     10/11/19    12/31/99  cross

预期成绩：

 id    start_dt    end_dt    type
 1     1/1/19      8/31/19   cross
 1     9/1/19      10/3/19   AAAA
 1     10/4/19     10/4/19   cross
 1     10/5/19     10/10/19  AAAA
 1     10/11/19    12/31/99  cross

我怎样才能让我的输出看起来像预期的结果？

我已经测试过lead lag rank，case expression但没有什么值得在这里添加的。我在正确的道路上吗？

标签： sqloracledatecyclegaps-and-islands

解决方案

这是一个gaps-and-islands问题。row_number()通过分析函数的贡献解决它的一种选择：

select min(start_dt) as startdate, max(end_dt) as enddate, type
  from
  (
   with t(id, start_dt, end_dt,type) as
   (
    select 1, date'2019-01-01', date'2019-02-21', 'cross' from dual union all
    select 1, date'2019-02-22', date'2019-06-05', 'cross'  from dual union all
    select 1, date'2019-06-06', date'2019-08-31', 'cross'  from dual union all  
    select 1, date'2019-09-01', date'2019-10-03', 'AAAA'  from dual union all
    select 1, date'2019-09-04', date'2019-10-04', 'cross'  from dual union all   
    select 1, date'2019-10-05', date'2019-10-06', 'AAAA'  from dual union all
    select 1, date'2019-10-07', date'2019-10-10', 'AAAA'  from dual union all  
    select 1, date'2019-10-11', date'2019-12-31', 'cross'  from dual 
   )
   select type, 
          row_number() over (partition by id, type order by end_dt) as rn1,
          row_number() over (partition by id order by end_dt) as rn2,
          start_dt, end_dt
     from t
   ) tt
 group by type, rn1 - rn2
 order by enddate;

STARTDATE   ENDDATE     TYPE
---------   ---------   -----
01-JAN-19   31-AUG-19   cross
01-SEP-19   03-OCT-19   AAAA
04-SEP-19   04-OCT-19   cross
05-OCT-19   10-OCT-19   AAAA
11-OCT-19   31-DEC-19   cross

Demo

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