如何在 SQL Bigquery 中计算另一个事件之前特定事件的数量？

Question

我有一个包含日期、事件和用户的表。有一个名为“A”的事件。我想找出 Sql Bigquery 中事件“A”之前和之后特定事件发生的次数。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

我必须计数的事件包含特定的前缀。意味着我必须检查以（ XY 然后是某个事件名称）开头的事件。因此，XYSomeEvent 是我必须设置计数器的事件。有什么建议么？

Answer 1

以下是 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

您可以使用问题中的虚拟数据进行测试

#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