提问人：mohannad mabrouk 提问时间：10/21/2023 最后编辑：Jensmohannad mabrouk 更新时间：10/21/2023 访问量：50
为什么它给我 GROUP BY Description_lenght_buckets作为无效列名称？[复制]
Why it's giving me that GROUP BY Description_lenght_buckets as Invalid Column name? [duplicate]
问：
SELECT
CASE
WHEN LEN(b.app_desc) < 500 THEN 'Short'
WHEN LEN(b.app_desc) BETWEEN 500 AND 1000 THEN 'Medium'
ELSE 'Long'
END AS Description_lenght_buckets, AVG(a.user_rating) AS Avg_rating
FROM AppleStore AS a
JOIN appleStore_description AS b
ON a.id = b.id
GROUP BY Description_lenght_buckets
ORDER BY Avg_rating
我尝试的唯一方法是使用 ALTER 创建新列，然后使用 GROUP BY，然后它会起作用。
此代码工作的唯一方法是使用 ALTER 吗？
答：
1赞
Lajos Arpad
10/21/2023
#1
您可以通过子选择来完成：
SELECT Description_lenght_buckets, AVG(user_rating) AS Avg_rating
FROM (
SELECT
CASE
WHEN LENGTH(b.app_desc) < 500 THEN 'Short'
WHEN LENGTH(b.app_desc) BETWEEN 500 AND 1000 THEN 'Medium'
ELSE 'Long'
END AS Description_lenght_buckets, user_rating
FROM AppleStore AS a
JOIN appleStore_description AS b
ON a.id = b.id
) t
GROUP BY Description_lenght_buckets
ORDER BY AVG(user_rating);
说明：您的子选择将选择要聚合的单个记录。
小提琴：http://sqlfiddle.com/#!5/79ba4/1
评论
0赞
Lajos Arpad
10/21/2023
@mohannadmabrouk很乐意提供帮助。
评论