BigQuery SQL：如何在比较日期范围内的两个表时查找缺失值？

Question

有两个Bigquery表如下所示：

Table 1:

Store   Report_Date
11      2021-03-03
12      2021-03-03
11      2021-04-14
13      2021-04-14

Table 2:

Store
11
12
13

场景： 与 Table 2 家商店相比，每个日期必须找到 Table 1 家缺失的商店。

预期输出： 在比较时列出每个日期的每个缺失商店。

MissingStore    Report_Date     
13              2021-03-03
12              2021-04-14

尝试查询： 但是这个查询没有显示相应的 Report_Date，而是显示 'null'.

 WITH
      tab1 AS (
      SELECT
        DISTINCT Store,
        Report_Date
      FROM
        tab1
        )
      
    SELECT
      DISTINCT tab2.Store, tab1.Report_Date
    FROM
      tab2
    LEFT JOIN
      tab1
    ON
      tab1.Store = tab2.Store
    WHERE  
      tab1.Store IS NULL

Answer 1

使用日历table方法：

SELECT s.Store AS MissingStore, d.Report_Date
FROM (SELECT DISTINCT Store FROM tab1) s
CROSS JOIN (SELECT DISTINCT Report_Date FROM tab1) d
INNER JOIN tab2 t2
    ON s.Store = t2.Store
LEFT JOIN tab1 t1
    ON t1.Store = s.Store AND t1.Report_Date = d.Report_Date
WHERE t1.Store IS NULL;

Answer 2

考虑以下方法

select a.Store MissingStore, b.Report_Date
from table2 a
cross join (select distinct Report_Date from table1) b
left join table1 c
using(Store, Report_Date)
where c.Report_Date is null

如果应用于您问题中的示例数据 - 输出为

BigQuery SQL：如何在比较日期范围内的两个表时查找缺失值？

BigQuery SQL: How to find missing Values on comparing two tables over date range?

sql

left-join

missing-data

google-bigquery