问题
I have a table containing date and events and users. There is event named 'A'. I want to find out how many time a particular event occurred before and after event 'A' in SQL Bigquery. The event A might appear multiple times. But it should count events only till it encounters another event A in both before and after condition.
for Example,
User Date Events
123 2018-02-14 X.Y.A
123 2018-02-12 X.Y.B
134 2018-02-10 Y.Z.A
123 2018-02-11 A
123 2018-02-01 X.Y.Z
134 2018-02-05 X.Y.B
134 2018-02-04 A
123 2018-02-13 A
The output would be something like this.
User Event Before After
123 A 1 1
123 A 0 1
134 A 0 1
The other condition remains same.
This question is an extension of my previous question.
See How to count number of a particular event before another event in SQL Bigquery? for details.
The event that I have to count contains a particular prefix. Means I have to check events that start with ( X.Y.then some event name). So, X.Y.SomeEvent are the events that I have to set the counter for. Any Suggestions?
回答1:
Below is for BigQuery Standard SQL
#standardSQL
WITH grps AS (
SELECT user, dt, event,
COUNTIF(event = 'A') OVER(PARTITION BY user ORDER BY dt) grp
FROM `project.dataset.events`
)
SELECT dt, user, event, before, after
FROM (
SELECT dt, user, event,
COUNTIF(event LIKE 'X.Y.%') OVER(PARTITION BY user ORDER BY grp RANGE BETWEEN 1 PRECEDING AND 1 PRECEDING ) before,
COUNTIF(event LIKE 'X.Y.%') OVER(PARTITION BY user ORDER BY grp RANGE BETWEEN CURRENT ROW AND CURRENT ROW) after
FROM grps
)
WHERE event = 'A'
-- ORDER BY user
you can test/play with above using dummy data from your example like below
#standardSQL
WITH `project.dataset.events` AS (
SELECT 123 user, '2018-02-14' dt, 'X.Y.A' event UNION ALL
SELECT 123, '2018-02-13', 'A' UNION ALL
SELECT 123, '2018-02-12', 'X.Y.B' UNION ALL
SELECT 123, '2018-02-11', 'A' UNION ALL
SELECT 123, '2018-02-01', 'X.Y.Z' UNION ALL
SELECT 134, '2018-02-10', 'Y.Z.A' UNION ALL
SELECT 134, '2018-02-05', 'X.Y.B' UNION ALL
SELECT 134, '2018-02-04', 'A'
), grps AS (
SELECT user, dt, event,
COUNTIF(event = 'A') OVER(PARTITION BY user ORDER BY dt) grp
FROM `project.dataset.events`
)
SELECT dt, user, event, before, after
FROM (
SELECT dt, user, event,
COUNTIF(event LIKE 'X.Y.%') OVER(PARTITION BY user ORDER BY grp RANGE BETWEEN 1 PRECEDING AND 1 PRECEDING ) before,
COUNTIF(event LIKE 'X.Y.%') OVER(PARTITION BY user ORDER BY grp RANGE BETWEEN CURRENT ROW AND CURRENT ROW) after
FROM grps
)
WHERE event = 'A'
ORDER BY user
with result as
Row dt user event before after
1 2018-02-11 123 A 1 1
2 2018-02-13 123 A 1 1
3 2018-02-04 134 A 0 1
回答2:
This is a more general question. Use can use the same ideas with lag() and lead():
select userid,
(seqnum - lag(seqnum, 1, 0) over (partition by userid, order by date) - 1) as before,
(lead(seqnum, 1, cnt) over (partition by user_id order by date) - seqnum - 1) as after
from (select t.*,
row_number() over (partition by userid order by date) as seqnum,
count(*) over (partition by userid) as cnt
from t
where event like 'X.Y%' or event = 'A'
) t
where event = 'A';
来源：https://stackoverflow.com/questions/48810682/count-number-of-events-before-and-after-a-event-a-till-another-event-a-is-en