BigQuery标准SQL按聚合多个列分组

样本数据集：

|ownerId|category|aggCategory1|aggCategory2|
--------------------------------------------
|  1    |  dog   |  animal    |   dogs     |
|  1    |  puppy |  animal    |   dogs     |
|  2    |  daisy |  flower    |   ignore   |
|  3    |  rose  |  flower    |   ignore   |
|  4    |  cat   |  animal    |   cats     |
 ...

正在查找包含类别、aggCategory1、aggCategory2中所有者数量的group by，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，但希望获得上述数据点

谢谢

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

分组依据

和与您的所有类别列的并集可以很好。

一种方法是使用

并集所有

来取消数据的并集，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

更大的查询方式是使用数组：

SELECT cat, COUNT(*)
FROM t CROSS JOIN
     UNNEST(ARRAY[category, aggcategory1, aggcategory2]) cat
GROUP BY cat;

---

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

---

您是否查看了

分组依据

和

计数

？如果你这样做了，问题是什么？