Wil*_*son 22 sql oracle select asset-management oracle12c
我有一张road_events桌子:
create table road_events (
event_id number(4,0),
road_id number(4,0),
year number(4,0),
from_meas number(10,2),
to_meas number(10,2),
total_road_length number(10,2)
);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (1,1,2020,25,50,100);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (2,1,2000,25,50,100);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (3,1,1980,0,25,100);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (4,1,1960,75,100,100);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (5,1,1940,1,100,100);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (6,2,2000,10,30,100);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (7,2,1975,30,60,100);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (8,2,1950,50,90,100);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (9,3,2050,40,90,100);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (10,4,2040,0,200,200);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (11,4,2013,0,199,200);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (12,4,2001,0,200,200);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (13,5,1985,50,70,300);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (14,5,1985,10,50,300);
insert into road_events (event_id, road_id, year, from_meas, to_meas, total_road_length) values (15,5,1965,1,301,300);
commit;
select * from road_events;
EVENT_ID ROAD_ID YEAR FROM_MEAS TO_MEAS TOTAL_ROAD_LENGTH
---------- ---------- ---------- ---------- ---------- -----------------
1 1 2020 25 50 100
2 1 2000 25 50 100
3 1 1980 0 25 100
4 1 1960 75 100 100
5 1 1940 1 100 100
6 2 2000 10 30 100
7 2 1975 30 60 100
8 2 1950 50 90 100
9 3 2050 40 90 100
10 4 2040 0 200 200
11 4 2013 0 199 200
12 4 2001 0 200 200
13 5 1985 50 70 300
14 5 1985 10 50 300
15 5 1965 1 301 300
我想选择代表每条道路上最近工作的事件.
这是一个棘手的操作,因为事件通常只涉及道路的一部分.这意味着我不能简单地选择每条道路最近的事件; 我只需要选择不重叠的最近事件里程.
可能的逻辑(按顺序):
我不愿意猜测这个问题是如何解决的,因为它可能最终会伤害到它的帮助(有点像XY问题).另一方面,它可能提供对问题性质的深入了解,所以它在这里:
event A.event A 是>= total_road_length,那就是我需要的全部.算法在这里结束.event B不具有相同范围的时间顺序事件()event A.event B重叠范围的范围event A,那么只获得event B那些不重叠的部分.= total_road_length.或者当没有更多事件发生时停止.题:
我知道这是一个很高的要求,但是要做什么呢？
这是一个经典的线性参考问题.如果我可以将线性引用操作作为查询的一部分,那将非常有用.
结果将是:
EVENT_ID ROAD_ID YEAR TOTAL_ROAD_LENGTH EVENT_LENGTH
---------- ---------- ---------- ----------------- ------------
1 1 2020 100 25
3 1 1980 100 25
4 1 1960 100 25
5 1 1940 100 25
6 2 2000 100 20
7 2 1975 100 30
8 2 1950 100 30
9 3 2050 100 50
10 4 2040 200 200
13 5 1985 300 20
14 5 1985 300 40
15 5 1965 300 240
相关问题:选择数字范围不重叠的位置
我的主要DBMS是Teradata,但这也可以在Oracle中使用.
WITH all_meas AS
( -- get a distinct list of all from/to points
SELECT road_id, from_meas AS meas
FROM road_events
UNION
SELECT road_id, to_meas
FROM road_events
)
-- select * from all_meas order by 1,2
, all_ranges AS
( -- create from/to ranges
SELECT road_id, meas AS from_meas
,Lead(meas)
Over (PARTITION BY road_id
ORDER BY meas) AS to_meas
FROM all_meas
)
-- SELECT * from all_ranges order by 1,2
, all_event_ranges AS
( -- now match the ranges to the event ranges
SELECT
ar.*
,re.event_id
,re.year
,re.total_road_length
,ar.to_meas - ar.from_meas AS event_length
-- used to filter the latest event as multiple events might cover the same range
,Row_Number()
Over (PARTITION BY ar.road_id, ar.from_meas
ORDER BY year DESC) AS rn
FROM all_ranges ar
JOIN road_events re
ON ar.road_id = re.road_id
AND ar.from_meas < re.to_meas
AND ar.to_meas > re.from_meas
WHERE ar.to_meas IS NOT NULL
)
SELECT event_id, road_id, year, total_road_length, Sum(event_length)
FROM all_event_ranges
WHERE rn = 1 -- latest year only
GROUP BY event_id, road_id, year, total_road_length
ORDER BY road_id, year DESC;
如果您需要返回实际覆盖from/to_meas(如编辑前的问题),可能会更复杂.第一部分是相同的,但是没有聚合,查询可以返回具有相同event_id的相邻行(例如,对于事件3:0-1和1-25):
SELECT * FROM all_event_ranges
WHERE rn = 1
ORDER BY road_id, from_meas;
如果要合并相邻的行,则需要两个步骤(使用标准方法,标记组的第1行并计算组号):
WITH all_meas AS
(
SELECT road_id, from_meas AS meas
FROM road_events
UNION
SELECT road_id, to_meas
FROM road_events
)
-- select * from all_meas order by 1,2
, all_ranges AS
(
SELECT road_id, meas AS from_meas
,Lead(meas)
Over (PARTITION BY road_id
ORDER BY meas) AS to_meas
FROM all_meas
)
-- SELECT * from all_ranges order by 1,2
, all_event_ranges AS
(
SELECT
ar.*
,re.event_id
,re.year
,re.total_road_length
,ar.to_meas - ar.from_meas AS event_length
,Row_Number()
Over (PARTITION BY ar.road_id, ar.from_meas
ORDER BY year DESC) AS rn
FROM all_ranges ar
JOIN road_events re
ON ar.road_id = re.road_id
AND ar.from_meas < re.to_meas
AND ar.to_meas > re.from_meas
WHERE ar.to_meas IS NOT NULL
)
-- SELECT * FROM all_event_ranges WHERE rn = 1 ORDER BY road_id, from_meas
, adjacent_events AS
( -- assign 1 to the 1st row of an event
SELECT t.*
,CASE WHEN Lag(event_id)
Over(PARTITION BY road_id
ORDER BY from_meas) = event_id
THEN 0
ELSE 1
END AS flag
FROM all_event_ranges t
WHERE rn = 1
)
-- SELECT * FROM adjacent_events ORDER BY road_id, from_meas
, grouped_events AS
( -- assign a groupnumber to adjacent rows using a Cumulative Sum over 0/1
SELECT t.*
,Sum(flag)
Over (PARTITION BY road_id
ORDER BY from_meas
ROWS Unbounded Preceding) AS grp
FROM adjacent_events t
)
-- SELECT * FROM grouped_events ORDER BY road_id, from_meas
SELECT event_id, road_id, year, Min(from_meas), Max(to_meas), total_road_length, Sum(event_length)
FROM grouped_events
GROUP BY event_id, road_id, grp, year, total_road_length
ORDER BY 2, Min(from_meas);
编辑:
Ups,我刚刚找到一个博客重叠范围优先级与一些简化的Oracle语法完全相同.事实上,我将我的查询从Teradata中的一些其他简化语法翻译为Standard/Oracle SQL :-)
还有另一种计算方法,包括from和to值:
with
part_begin_point as (
Select distinct road_id, from_meas point
from road_events be
union
Select distinct road_id, to_meas point
from road_events ee
)
, newest_part as (
select e.event_id
, e.road_id
, e.year
, e.total_road_length
, p.point
, LAG(e.event_id) over (partition by p.road_id order by p.point) prev_event
, e.to_meas event_to_meas
from part_begin_point p
join road_events e
on p.road_id = e.road_id
and p.point >= e.from_meas and p.point < e.to_meas
and not exists(
select 1 from road_events ne
where e.road_id = ne.road_id
and p.point >= ne.from_meas and p.point < ne.to_meas
and (e.year < ne.year or e.year = ne.year and e.event_id < ne.event_id))
)
select event_id, road_id, year
, point from_meas
, LEAD(point, 1, event_to_meas) over (partition by road_id order by point) to_meas
, total_road_length
, LEAD(point, 1, event_to_meas) over (partition by road_id order by point) - point EVENT_LENGTH
from newest_part
where 1=1
and event_id <> prev_event or prev_event is null
order by event_id, point