如何在 SQL Bigquery 中计算另一个事件之前特定事件的数量？

Question

我有一个 table 包含日期、事件和用户。有一个名为 'A' 的事件。我想知道在 Sql Bigquery 中的事件 'A' 之前和之后特定事件发生了多少次。例如，

   User           Date             Events
    123          2018-02-13            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

输出会是这样的

User       Event    Before   After
123          A      1        3
134          A      0        1

我必须计算的事件包含一个特定的前缀。意味着我必须检查以（ X.Y.then 某些事件名称）开头的事件。因此，X.Y.SomeEvent 是我必须为其设置计数器的事件。有什么建议吗？

Answer 1

用户window函数查找"A"发生的日期。然后使用条件聚合统计前后事件：

select userid,
       sum(case when date < a_date and event like 'X.Y%' then 1 else 0 end) as before,
       sum(case when date > a_date and event like 'X.Y%' then 1 else 0 end) as before
from (select t.*,
             min(case when event = 'A' then date end) over (partition by userid) as a_date
      from t
     ) t
group by userid

Answer 2

以下适用于 BigQuery SQL

#standardSQL
SELECT user, event, before, after 
FROM (
  SELECT user, event, 
    COUNTIF(event LIKE 'X.Y.%') OVER(PARTITION BY user ORDER BY dt ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING) before,
    COUNTIF(event LIKE 'X.Y.%') OVER(PARTITION BY user ORDER BY dt ROWS BETWEEN 1 FOLLOWING AND UNBOUNDED FOLLOWING ) after
  FROM `project.dataset.events`
)
WHERE event = 'A'
-- ORDER BY user

你可以在你的问题中用虚拟数据测试它

#standardSQL
WITH `project.dataset.events` AS (
  SELECT 123 user, '2018-02-13' dt, 'X.Y.A' event UNION ALL
  SELECT 123, '2018-02-12', 'X.Y.B' UNION ALL
  SELECT 123, '2018-02-11', 'A' 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' UNION ALL
  SELECT 123, '2018-02-01', 'X.Y.Z' 
)
SELECT user, event, before, after 
FROM (
  SELECT user, event, 
    COUNTIF(event LIKE 'X.Y.%') OVER(PARTITION BY user ORDER BY dt ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING) before,
    COUNTIF(event LIKE 'X.Y.%') OVER(PARTITION BY user ORDER BY dt ROWS BETWEEN 1 FOLLOWING AND UNBOUNDED FOLLOWING ) after
  FROM `project.dataset.events`
)
WHERE event = 'A'
ORDER BY user

如何在 SQL Bigquery 中计算另一个事件之前特定事件的数量？

How to count number of a particular event before another event in SQL Bigquery?

sql

google-bigquery

legacy-sql