用于在两个表中匹配列的SQL查询

Question

我有两个SQL表：users＆amp; userGroup包含以下数据：

用户：

 user      | age | gender

    testUserA,  25,   Male
    testUserB,  30,   Female
    testUserC,  35,   Male

userGroup ：

user     | group

testUserA, groupA
testUserB, groupA
testUserC, groupB

我如何用短语查询以列出groupA中的男性用户？

Answer 1

您只需要join和where子句来过滤gender和group：

select u.user
from user u
join userGroup ug on u.user = ug.user
where u.gender = 'Male'
  and ug.group = 'groupA'

Answer 2

此查询会将两个表连接在一起，并按性别进行过滤。

SELECT u.User, u.Gender, ug.Group
FROM user u
INNER JOIN userGroup ug
ON u.user = ug.user
WHERE u.gender = 'Male'
AND ug.Group = 'groupA';

Answer 3

以下是一种方法：

select a.user, a.age, a.gender, b.group from users as a 
inner join userGroup as b on a.user=b.user 
where a.gender='Male' and b.group='groupA'