如何解决在SQL中检测和合并日期范围的连续重叠
我需要检测并合并表中的重叠日期范围,但仅在连续的行中,不成功的重叠将被忽略。
CREATE TABLE konto (konto_nummer INTEGER,start_datum DATE,end_datum DATE);
INSERT INTO konto VALUES (1,'2020-01-01 00:00:00.000000','2020-01-10 00:00:00.000000');
INSERT INTO konto VALUES (1,'2020-01-12 00:00:00.000000','2020-01-20 00:00:00.000000');
INSERT INTO konto VALUES (2,'2020-01-10 00:00:00.000000');
INSERT INTO konto VALUES (2,'2020-01-05 00:00:00.000000','2020-01-15 00:00:00.000000','2020-01-25 00:00:00.000000');
INSERT INTO konto VALUES (2,'2020-02-05 00:00:00.000000','2020-02-20 00:00:00.000000');
INSERT INTO konto VALUES (3,'2020-01-25 00:00:00.000000');
INSERT INTO konto VALUES (4,'2020-04-01 00:00:00.000000','2020-04-10 00:00:00.000000');
INSERT INTO konto VALUES (4,'2020-04-05 00:00:00.000000','2020-04-15 00:00:00.000000');
INSERT INTO konto VALUES (4,'2020-04-16 00:00:00.000000','2020-04-25 00:00:00.000000');
INSERT INTO konto VALUES (4,'2020-04-20 00:00:00.000000','2020-04-30 00:00:00.000000');
相同颜色的行具有连续的重叠。
我尝试了以下
SELECT
ROW_NUMBER () OVER (ORDER BY konto_nummer,start_datum,end_datum) AS RN,konto_nummer,end_datum,MAX(end_datum) OVER (PARTITION BY konto_nummer ORDER BY start_datum,end_datum ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING) AS Previousend_datum
FROM konto;
但是它也结合了非连续的重叠。
解决方法
差距和离岛有多个步骤。
首先,标记差距
with mark as (
select *,lag(end_datum) over w
not between start_datum and end_datum as island
from konto
window w as (partition by konto_nummer
order by start_datum,end_datum)
),
然后,编号岛屿
grps as (
select *,sum(coalesce(island,true)::int) over w as grpnum
from mark
window w as (partition by konto_nummer
order by start_datum,end_datum)
)
然后按组汇总
select konto_nummer,min(start_datum) as start_datum,max(end_datum) as end_datum
from grps
group by konto_nummer,grpnum
order by 1,2,3;
,
当重叠可以是任意的时,我更喜欢使用累积最大值来找到它们,而不是lag()
。在这样的情况下可以正常工作:
A ------- B -------- B --------------C-C-------A
这是:
select konto_nummer,min(start_datum),max(end_datum)
from (select k.*,count(*) filter (where prev_end_datum is null or prev_end_datum < start_datum) over
(partition by konto_nummer order by start_datum) as grp
from (select k.*,max(end_datum) over (partition by konto_nummer order by start_datum range between unbounded preceding and '1 second' preceding) as prev_end_datum
from konto k
) k
) k
group by konto_nummer,grp
order by konto_nummer,min(start_datum);
Here是db 小提琴。
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