加入2个表并得到巧合的总和

Question

注册用户的表格：

• id_user
• id_location
• 名称

来自地点的表格：

• id_location
• 名称

我需要知道每个位置有多少用户。像这样：

• 华盛顿：455
• 佛罗里达州：185
• 德克萨斯州：914

尝试了这种方法，但结果肯定是错误。

SELECT location.name,user.id_user FROM user
INNER JOIN location ON user.id_location = location.id_location
WHERE user.id_profile !=0 GROUP BY location.id_location ORDER BY location.name

Answer 1

SELECT location.id_location, location.name, COUNT(user.id_user) AS UserCount
FROM user 
INNER JOIN location ON user.id_location = location.id_location 
WHERE user.id_profile !=0 
GROUP BY location.id_location, location.name
ORDER BY location.name 

我已将id_location添加到查询中，以防您以某种方式拥有相同的位置名称，但位置ID不同。

Answer 2

你真的很亲密，你只需要做COUNT：

SELECT location.name, COUNT(user.id_user) UserCount 
FROM user
INNER JOIN location 
ON user.id_location = location.id_location
WHERE user.id_profile !=0 
GROUP BY location.name
ORDER BY location.name