Question

从这里可用的世界数据库http://downloads.mysql.com/docs/world.sql.gz我想只显示说超过5种语言的国家/地区的名称：

我试过这个：

SELECT 
    country.Name, COUNT(countrylanguage.Language) as languages
FROM 
    country, countrylanguage
WHERE 
    country.Code = countrylanguage.CountryCode 
GROUP BY 
    country.Name
HAVING 
    languages >= 6

但问题是，它是否也显示了语言的数量，我想要的只是列country.Name。

谢谢。

Answer 1

以下是TinTran评论的答案：

SELECT country.Name FROM country, countrylanguage WHERE country.Code = countrylanguage.CountryCode Group BY country.Name HAVING COUNT(countrylanguage.Language) >= 6

Answer 2

使用ANSI样式INNER JOIN。

SELECT country.Name
FROM country INNER JOIN countrylanguage
ON country.Code = countrylanguage.CountryCode 
Group BY country.Name
HAVING COUNT(countrylanguage.Language) >= 6

在sql中过滤列

2 个答案: