Impala SQL：合并具有重叠日期的行。不支持WHERe EXISTS和递归CTE

Impala SQL：合并具有重叠日期的行。不支持WHERe EXISTS和递归CTE

select min(StartDate) as StartDate
,max(EndDate) as EndDate

from   (select  StartDate,EndDate    ,count (is_gap) over     (         order by    StartDate,ID     )   as range_id        from   (select  ID,StartDate,EndDate ,case       when    max (EndDate) over   (       order by    StartDate,ID       rows        between unbounded preceding         and     1 preceding   ) < StartDate      then    true  end as is_gap     from    t     ) t        ) tgroup by    range_idorder by    StartDate;

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+------------+------------+| startdate  | enddate    |+------------+------------+| 2017-01-01 | 2017-04-01 || 2017-05-05 | 2017-08-31 || 2017-10-01 | 2017-10-05 || 2017-11-01 | 2017-12-25 |+------------+------------+