Firebase 如何在google BigQuery中填写缺失的日期

我想写一个图表，显示firebase中的活动用户

我写了这段代码

SELECT event_date, COUNT(DISTINCT user_pseudo_id) AS user_count
FROM `mark-3314e.analytics_197261162.events_*`  
WHERE _TABLE_SUFFIX BETWEEN FORMAT_DATE('%Y%m%d', DATE_SUB(CURRENT_DATE(), INTERVAL 7 DAY)) AND FORMAT_DATE('%Y%m%d', CURRENT_DATE())
AND event_name = 'session_start'
GROUP BY event_date
ORDER BY event_date ASC

这就是答案

Row event_date  user_count  
1   20190617        1
2   20190621        3

有没有办法用以前的数据来填补21日至17日之间缺失的日期？比如：

event_date  user_count  
20190617        1
20190618        1
20190619        1
20190620        1
20190621        3

---

您可以加入包含完整日期范围的日历表：

WITH dates AS (
    SELECT '20190617' AS dt UNION ALL
    SELECT '20190618' UNION ALL
    SELECT '20190619' UNION ALL
    SELECT '20190620' UNION ALL
    SELECT '20190621'
)

SELECT
    t1.dt AS event_date,
    COUNT(DISTINCT t2.user_pseudo_id) AS user_count
FROM dates t1
LEFT JOIN `mark-3314e.analytics_197261162.events_*` t2
    ON t1.dt = t2.event_date AND
       t2._TABLE_SUFFIX BETWEEN FORMAT_DATE('%Y%m%d', DATE_SUB(CURRENT_DATE(), INTERVAL 7 DAY)) AND FORMAT_DATE('%Y%m%d', CURRENT_DATE())
       AND t2.event_name = 'session_start'
GROUP BY
    t1.dt
ORDER BY
    t1.dt;

---

对于在BigQuery中生成日期范围的更通用的方法，.

这里有一个可能的解决方案，使用BigQuery中的

生成日期数组

函数

with data as (
   SELECT parse_date('%Y%m%d', event_date) AS event_date, COUNT(DISTINCT user_pseudo_id) AS user_count
   FROM `mark-3314e.analytics_197261162.events_*`  
   WHERE _TABLE_SUFFIX BETWEEN FORMAT_DATE('%Y%m%d', DATE_SUB(CURRENT_DATE(), INTERVAL 7 DAY)) AND FORMAT_DATE('%Y%m%d', CURRENT_DATE())
   AND event_name = 'session_start'
   GROUP BY event_date
   ORDER BY event_date ASC
)

select dt as event_date, user_count from (
  select user_count,
      if(
        previousdate is null, 
        generate_date_array(date, date_sub(nextdate, interval 1 day), interval 1 day), 
        generate_date_array(date, if(nextdate is null, date, date_sub(nextdate, interval 1 day)), interval 1 day)
      ) as dates 
  from (
          select 
            lag(event_date) over(order by event_date) as previousdate,
            event_date as date,
            lead(event_date) over(order by event_date) as nextdate,
            user_count
          from data
      )
), unnest(dates) dt

---

我不得不在

组中通过t2.dt通过t1改变t2，因为它不起作用。。。然后，它仍然向我显示相同的结果（20190617 1）和（20190621 3）@AymenFezai尝试将
WHERE
子句中的所有逻辑移动到join的
ON
子句中。我犯了错误，应该从一开始就这样做。它用零填充缺少的数据，但应该用以前的结果填充它们。我的意思是，像这样的：（20190617 1），（20190618 1），（20190619 1）和（20190621 3）这个要求没有出现在你原来的问题中。是的，很抱歉