[英]BigQuery Standard SQL Group by aggregate multiple columns
示例数据集:
|ownerId|category|aggCategory1|aggCategory2|
--------------------------------------------
| 1 | dog | animal | dogs |
| 1 | puppy | animal | dogs |
| 2 | daisy | flower | ignore |
| 3 | rose | flower | ignore |
| 4 | cat | animal | cats |
...
希望做一个包含来自类别、aggCategory1、aggCategory2 的所有者数量的分组,例如输出:
|# of owners|summaryCategory|
-----------------------------
| 1 | dog |
| 1 | puppy |
| 1 | daisy |
| 1 | rose |
| 1 | cat |
| 2 | animal |
| 2 | flower |
| 1 | dogs |
| 2 | ignore |
| 1 | cats |
不必是那种格式,而是希望获得上述数据点。
谢谢!
一种方法是使用union all
对数据进行反透视,然后在外部查询中进行聚合:
SELECT category, COUNT(*)
FROM (SELECT ownerID, category
FROM t
UNION ALL
SELECT ownerID, aggCategory1
FROM t
UNION ALL
SELECT ownerID, aggCategory2
FROM t
) t
GROUP BY category
更 BigQuery 的写法是使用数组:
SELECT cat, COUNT(*)
FROM t CROSS JOIN
UNNEST(ARRAY[category, aggcategory1, aggcategory2]) cat
GROUP BY cat;
SELECT COUNT(T.ownerID), T.category
FROM (
SELECT ownerID, category
FROM table
UNION
SELECT ownerID, aggCategory1
FROM table
UNION
SELECT ownerID, aggCategory2
FROM table
) AS T
GROUP BY T.category
使用GROUP BY
和与您所有类别列的并集,效果会很好。
使用union all
with cte as
(
SELECT ownerID, category as summaryCategory
FROM table
UNION
SELECT ownerID, aggCategory1 as summaryCategory
FROM table
UNION
SELECT ownerID, aggCategory2 as summaryCategory
FROM table
) select count(ownerID),summaryCategory from cte group by summaryCategory
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