蜂巢-在一列中计算不同的CSV

其中一个蜂巢表如下所示：

 ID    listOfcategories
    1     ["a","b","b","a","c","d","d"]
    2     ["a","a","a","c","c","c","c","e","e","e"]
    3     ["a","b","c"]

逗号分隔值的数量是一个变量。我想查询每个行/ID中不同类别的数量。 因此，我的输出应该如下所示：

ID     numDistCategories
1      4
2      3
3      3

---

您可以使用

explode

to，然后使用

count distinct

获得您要查找的结果

像这样的

SELECT 
    id, 
    COUNT(DISTINCT(cat)) as numDistCategories
FROM (
    SELECT 
        id, 
        EXPLODE(listOfcategories) AS cat 
    FROM myTable) a
GROUP BY id;

希望有帮助