2

谁能指导我为以下场景编写 MySQL 查询。

表中的数据是这样的，

Table Name: user

user_id     country     city            age
----------------------------------------------
1           India       Mumbai          22
2           India       Mumbai          22
3           India       Delhi           22
4           India       Delhi           23
5           India       Chennai         23
6           China       Beijing         20
7           China       Beijing         20
8           China       Shanghai        20
9           USA         New York        30
10          USA         New York        30
11          USA         New York        30
12          USA         Los Angeles     31
13          USA         Los Angeles     31
14          USA         Los Angeles     40

我希望结果是这样的，基本上是特定国家城市中所有年龄相同的用户的总和。

country     city            age     age_count
----------------------------------------------
India       Mumbai          22          2
India       Delhi           22          1
India       Delhi           23          1
India       Chennai         23          1
China       Beijing         20          2
China       Shanghai        20          1
USA         New York        30          3
USA         Los Angeles     31          2
USA         Los Angeles     40          1
4

2 回答 2

3

试试这个 ：;

SELECT country,
       city,
       age,
       count(user_id) AS age_count
FROM user
GROUP BY country,
         city,
         round(age)
于 2012-11-28T13:15:40.353 回答
3 
select country, city, age, count(*) age_count
from user 
group by country, city, age
于 2012-11-28T13:15:45.023 回答