Sql 重写查询以使用分析函数
我有一个事件表,记录事件的插入、更新和删除。 见MWE her: DDL语句Sql 重写查询以使用分析函数,sql,oracle,analytics,Sql,Oracle,Analytics,我有一个事件表,记录事件的插入、更新和删除。 见MWE her: DDL语句 CREATE TABLE "EVENTS" ( "EVENT_ID" VARCHAR2(30 CHAR), --Name of the Event "EVENT_LOCATION" VARCHAR2(60 CHAR), --Location on which the event occured "EVENT_TRIGGER" VARCHAR2(2 CHAR), --Trigger wh
CREATE TABLE "EVENTS"
(
"EVENT_ID" VARCHAR2(30 CHAR), --Name of the Event
"EVENT_LOCATION" VARCHAR2(60 CHAR), --Location on which the event occured
"EVENT_TRIGGER" VARCHAR2(2 CHAR), --Trigger which protocolled the event (I,U or D)
"EVENT_CHANGE_ID" NUMBER, --Unique Sequence Number
"EVENT_CHANGE_DATE" DATE DEFAULT SYSTIMESTAMP
);
INSERT INTO EVENTS (EVENT_ID,EVENT_LOCATION,EVENT_TRIGGER,EVENT_CHANGE_ID,EVENT_CHANGE_DATE)
VALUES ('EVENT1','LOC1','I',1,SYSTIMESTAMP-1);
INSERT INTO EVENTS (EVENT_ID,EVENT_LOCATION,EVENT_TRIGGER,EVENT_CHANGE_ID,EVENT_CHANGE_DATE)
VALUES ('EVENT1','LOC2','U',11,SYSTIMESTAMP-1);
INSERT INTO EVENTS (EVENT_ID,EVENT_LOCATION,EVENT_TRIGGER,EVENT_CHANGE_ID,EVENT_CHANGE_DATE)
VALUES ('EVENT1','LOC4','U',117,SYSTIMESTAMP-1);
INSERT INTO EVENTS (EVENT_ID,EVENT_LOCATION,EVENT_TRIGGER,EVENT_CHANGE_ID,EVENT_CHANGE_DATE)
VALUES ('EVENT1','LOC7','D',1430,SYSTIMESTAMP-1);
INSERT INTO EVENTS (EVENT_ID,EVENT_LOCATION,EVENT_TRIGGER,EVENT_CHANGE_ID,EVENT_CHANGE_DATE)
VALUES ('EVENT2','LOC1','I',2,SYSTIMESTAMP-1/48);
INSERT INTO EVENTS (EVENT_ID,EVENT_LOCATION,EVENT_TRIGGER,EVENT_CHANGE_ID,EVENT_CHANGE_DATE)
VALUES ('EVENT2','LOC2','U',131,SYSTIMESTAMP-1/48);
INSERT INTO EVENTS (EVENT_ID,EVENT_LOCATION,EVENT_TRIGGER,EVENT_CHANGE_ID,EVENT_CHANGE_DATE)
VALUES ('EVENT2','LOC5','D',11337,SYSTIMESTAMP-1/48);
INSERT INTO EVENTS (EVENT_ID,EVENT_LOCATION,EVENT_TRIGGER,EVENT_CHANGE_ID,EVENT_CHANGE_DATE)
VALUES ('EVENT2','LOC7','D',14430,SYSTIMESTAMP-1/48);
我想确定在LOC1插入并在LOC7删除的事件数量,其间没有任何删除
SELECT COUNT(*) AS QTY, TRUNC(A.EVENT_CHANGE_DATE) AS DAY
FROM (
SELECT EVENT_ID, EVENT_CHANGE_ID, EVENT_CHANGE_DATE FROM EVENTS WHERE EVENT_TRIGGER = 'I' AND EVENT_LOCATION = 'LOC1'
) A,
(SELECT EVENT_ID, EVENT_CHANGE_ID, EVENT_CHANGE_DATE FROM EVENTS WHERE EVENT_TRIGGER = 'D' AND EVENT_LOCATION = 'LOC7')
B
WHERE B.EVENT_CHANGE_ID > A.EVENT_CHANGE_ID AND A.EVENT_ID = B.EVENT_ID
AND not exists (SELECT EVENT_ID, EVENT_CHANGE_ID, EVENT_CHANGE_DATE FROM EVENTS WHERE EVENT_TRIGGER = 'D' AND EVENT_CHANGE_ID > A.EVENT_CHANGE_ID AND EVENT_CHANGE_ID < B.EVENT_CHANGE_ID and EVENT_ID = A.EVENT_ID)
group by TRUNC(A.EVENT_CHANGE_DATE)
ORDER BY TRUNC(A.EVENT_CHANGE_DATE);
我的天真方法是可行的,但是我想知道是否可以使用分析函数重写这个查询。
原始表包含多达100万条记录。就执行时间和性能而言,3倍全表扫描是一个错误
甚至可以通过分析函数使此查询更高效吗?这看起来非常适合SQL模式匹配:
select * from events
match_recognize (
partition by event_id
order by event_change_date
measures
count ( ins.* ) ins_count,
min ( event_change_date ) dt
pattern ( ins upd* del )
define
ins as event_trigger = 'I' and event_location = 'LOC1',
upd as event_trigger = 'U',
del as event_trigger = 'D' and event_location = 'LOC7'
);
INS_COUNT DT
1 16-MAR-2020 12:33:58
这将在LOC1处搜索INSERT,然后在LOC7处搜索Delete,其间有任意数量的更新。仅使用经典分析函数 仅过滤相关事件
(EVENT_TRIGGER = 'I' AND EVENT_LOCATION = 'LOC1') OR -- only LOC1 inserts
EVENT_TRIGGER = 'D') -- all deletes
然后引导下一次删除并检查位置
with evnt as
(
select EVENT_ID, EVENT_LOCATION, EVENT_TRIGGER, EVENT_CHANGE_DATE,
lead(EVENT_TRIGGER) over (PARTITION BY EVENT_ID
order by EVENT_CHANGE_DATE, EVENT_LOCATION)
as EVENT_TRIGGER_LEAD,
lead(EVENT_LOCATION) over (PARTITION BY EVENT_ID
order by EVENT_CHANGE_DATE, EVENT_LOCATION)
as EVENT_LOCATION_LEAD
from EVENTS
where (EVENT_TRIGGER = 'I' AND EVENT_LOCATION = 'LOC1') OR EVENT_TRIGGER = 'D'
)
select
EVENT_ID, EVENT_LOCATION, EVENT_TRIGGER, EVENT_CHANGE_DATE,
EVENT_TRIGGER_LEAD, EVENT_LOCATION_LEAD
from evnt
where EVENT_TRIGGER = 'I'
and EVENT_TRIGGER_LEAD = 'D'
and EVENT_LOCATION_LEAD = 'LOC7'
order by EVENT_ID, EVENT_CHANGE_DATE, EVENT_LOCATION;
可以使用分析函数SUM将1添加到结果中(当其为LOC1和I时),并将-1添加到结果中(当其为D时),则最终结果将是SUM=0且位置为LOC7的记录 请看答案:
SQL> SELECT EVENT_ID FROM
2 ( SELECT SUM(CASE
3 WHEN EVENT_LOCATION = 'LOC1' AND EVENT_TRIGGER = 'I' THEN 1
4 WHEN EVENT_TRIGGER = 'D' THEN - 1
5 END) OVER( PARTITION BY EVENT_ID ORDER BY EVENT_CHANGE_DATE ) AS SM,
6 T.*
7 FROM EVENTS T
8 ) T
9 WHERE EVENT_LOCATION = 'LOC7' AND SM = 0;
EVENT_ID
------------
EVENT1
SQL>
干杯 使用铅分析功能:
SELECT COUNT(*) as qty,
TRUNC(event_change_date)day
FROM(
SELECT
event_location,
event_trigger,
event_change_date,
lead(event_trigger)
OVER(PARTITION BY trunc(event_change_date)
ORDER BY to_number(substr(event_location, - 1, 1))) rn
FROM events
) WHERE event_trigger <> 'D'
AND rn <> 'D'
AND event_trigger = rn
GROUP BY trunc(event_change_date);
QTY DAY
---------- --------
1 16-03-20
逻辑:
将每天的事件分组,并使用SUBSTR根据位置从1到7进行排序,然后从字符串的背面获取数字。
使用LEAD将事件触发与其LEAD进行比较。
每个日期的分区组中的事件_触发器不应具有从1到7的DELETE。
在问题中包括代码。不要依赖外部站点。不起作用我更新了问题,不知怎的sqlfiddle不起作用匹配的好例子!非常好的解决方案。以前从未听说过,但这是一个强大的工具。有趣的方法,仅限于所有删除都跟随插入,并且在同一位置没有重复插入的情况。