如何 GROUP BY BigQuery 中的外键？

Question

我在 BigQuery 工作。我有三个 table：分支机构、地区（分支机构的集合）和按分支机构每月支出。

CREATE TABLE region (
    id integer NOT NULL,
    name varchar NOT NULL
);
CREATE TABLE branch (
    id integer NOT NULL,
    name varchar NOT NULL,
    region integer NOT NULL 
);
CREATE TABLE spend (
   branch integer NOT NULL
   amount float,
   month timestamp,
   item_code int
);

如何按地区按月计算总支出？

我有这个按分行按月计算的总支出：

SELECT branch, 
       month, 
       SUM(amount) AS total_amount
FROM [mytable]
GROUP BY branch, 
         month

但我不知道如何按地区分组。我想我在某处需要一个 IN 子句？

它也是一个相当大的数据集（spend table 中有 150GB/500m 行），因此大型 JOIN 可能无法工作。

Answer 1

据推测，您需要连接和聚合，我很确定 Bigquery 支持：

SELECT b.region, s.month,  SUM(s.amount) AS total_amount
FROM spend s join
     branch b
     ON s.branch = b.id
GROUP BY b.region, s.month;

Answer 2

SELECT r.name as region, [month], SUM(total_amount) AS total_amount 
FROM (
  SELECT branch, [month], SUM(amount) AS total_amount
  FROM [mydataset.spend]
  GROUP EACH BY branch, [month]
) AS s
JOIN [mydataset.branch] AS b ON s.branch = b.id
JOIN [mydataset.region] AS r ON b.region = r.id
GROUP BY 1, 2

GROUP EACH BY 和 sub-select 中的 pre-grouping 用于解决您的问题：large JOINs may not work。

如何 GROUP BY BigQuery 中的外键？

How to GROUP BY a foreign key in BigQuery?

sql

google-bigquery