BigQuery SQL：过滤事件序列

Question

我想数一数，对于每个 app_id，event_type: store_app_view 之后有多少次 event_type: store_app_download同一用户（"followed" 意味着 store_app_view 的 event_time_utc 比 store_app_download 的 event_time_utc 更老）。

示例数据：

WITH 
`project.dataset.dummy_data_init` AS (SELECT event_id FROM UNNEST(GENERATE_ARRAY(1, 10000)) event_id),

`project.dataset.dummy_data_completed` AS (SELECT event_id,
    user_id[OFFSET(CAST(20 * RAND() - 0.5 AS INT64))] user_id,
    app_id[OFFSET(CAST(100 * RAND() - 0.5 AS INT64))] app_id,
    event_type[OFFSET(CAST(6 * RAND() - 0.5 AS INT64))] event_type,
    event_time_utc[OFFSET(CAST(26 * RAND() - 0.5 AS INT64))] event_time_utc
  FROM `project.dataset.dummy_data_init`, 
     (SELECT GENERATE_ARRAY(1, 20) user_id),
     (SELECT GENERATE_ARRAY(1, 100) app_id),
     (SELECT ['store_app_view', 'store_app_view', 'store_app_download','store_app_install','store_app_update','store_fetch_manifest'] event_type),
     (SELECT GENERATE_TIMESTAMP_ARRAY('2020-01-01 00:00:00', '2020-01-26 00:00:00',
                                INTERVAL 1 DAY) AS event_time_utc))

Select * FROM `project.dataset.dummy_data_completed`

谢谢！

Answer 1

I want to count, for each app_id, how many times the event_type: store_app_view was followed by the event_type: store_app_download.

你提供的查询似乎与这个问题几乎没有联系，所以我会忽略它。

对于每个 user/app 对，您可以使用 GROUP BY:

获取符合条件的行

select user_id, app_id
from t
group by user_id, app_id
having min(case when event_type = 'store_app_view' then event_time end) <
       max(case when event_type = 'store_app_download' then event_time end);

要获取每个 app 的总数，请使用子查询或 CTE：

select app_id, count(*)
from (select user_id, app_id
      from t
      group by user_id, app_id
      having min(case when event_type = 'store_app_view' then event_time end) <
             max(case when event_type = 'store_app_download' then event_time end)
     ) ua
group by app_id;

BigQuery SQL：过滤事件序列

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