如何在Google BigQuery中从“网站上的MAU平均时间”更改为“网站上的DAU平均时间”？

Question

我对使用Google BigQuery非常陌生。我目前有一个查询，写的是“每个MAU的平均现场时间”（请参阅​​下文）。我需要更改此查询以拉出“每个DAU的网站平均时间”。我在使用BQ语法时遇到困难。

*请注意，我已经用table1替换了实际的表名，依此类推。

WITH
   base AS (
   SELECT
     *
   FROM (
     SELECT
       _TABLE_SUFFIX AS table_date,
       "web" AS app_source,
       *
     FROM
       `table1`
     UNION ALL
     SELECT
       _TABLE_SUFFIX AS table_date,
       "iOS" AS app_source,
       *
     FROM
       `table2`
     UNION ALL
     SELECT
       _TABLE_SUFFIX AS table_date,
       "Android" AS app_source,
       *
     FROM
       `table3` )
   WHERE
     NOT REGEXP_CONTAINS(table_date, "intraday|backup") )
SELECT
   FORMAT_DATE("%E4Y-%m", PARSE_DATE("%E4Y%m%d", table_date)) as yearMonth,
   FORMAT_DATE("%E4Y-%m-01", PARSE_DATE("%E4Y%m%d", MIN(table_date))) AS 
ymd,
   AVG(COALESCE(totals.timeOnSite, totals.timeOnScreen, 0)) as timeOnSite
  FROM
   base
WHERE
   table_date > "20180101"
   GROUP BY 1
ORDER BY 1