SQL - 如果日期连接则合并行

Question

我有包含以下行的表:clientid、startdate 和 enddate。同一 clientid 的日期不能重叠。如果日期连接，我想为每个客户合并行。

表格看起来像这样:

clientid  startdate      enddate
1         10.10.2017     12.10.2017
1         12.10.2017     13.10.2017
1         13.10.2017     17.10.2017
1         10.11.2017     17.11.2017
1         17.11.2017     23.11.2017
1         12.12.2017     14.12.2017
2         10.11.2017     15.11.2017
2         01.12.2017     02.12.2017
2         02.12.2017     05.12.2017

决赛 table 应该是这样的:

clientid  startdate      enddate
    1     10.10.2017     17.10.2017
    1     10.11.2017     23.11.2017
    1     12.12.2017     14.12.2017
    2     10.11.2017     15.11.2017
    2     01.12.2017     05.12.2017

谢谢你的帮助。

Answer 1

您可以将这样的逻辑与 sum 聚合和 lag 窗口函数一起使用，如下所示:

select clientid, min(startdate) as startdate, max(enddate) as enddate
  from
(
select tt.*, sum(grp) over (order by clientid, startdate) sm 
  from
(
  with t(clientid, startdate, enddate) as
  (
   select 1, date'2017-10-10', date'2017-10-12' from dual union all
   select 1, date'2017-10-12', date'2017-10-13' from dual union all
   select 1, date'2017-10-13', date'2017-10-17' from dual union all  
   select 1, date'2017-11-10', date'2017-11-17' from dual union all  
   select 1, date'2017-11-17', date'2017-11-23' from dual union all  
   select 1, date'2017-12-12', date'2017-12-14' from dual union all
   select 2, date'2017-11-10', date'2017-11-15' from dual union all  
   select 2, date'2017-12-01', date'2017-12-02' from dual union all  
   select 2, date'2017-12-02', date'2017-12-05' from dual
  )
 select clientid, 
        decode(nvl(lag(enddate) over 
                   (order by enddate),startdate),startdate,0,1) 
                   as grp, --> means prev. value equals or not 
        row_number() over (order by clientid, enddate) as rn, startdate, enddate
    from t
) tt
order by rn
) 
group by clientid, sm 
order by clientid, enddate;

CLIENTID    STARTDATE   ENDDATE
----------  ----------  ----------
1           10.10.2017  17.10.2017
1           10.11.2017  23.11.2017
1           12.12.2017  14.12.2017
2           10.11.2017  15.11.2017
2           01.12.2017  05.12.2017

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