题解 | 查找山东大学或者性别为男生的信息

SELECT device_id, gender, age, gpa
FROM user_profile
WHERE university = '山东大学' 

union all

SELECT device_id, gender, age, gpa
FROM user_profile
WHERE  gender ='male';

SELECT device_id, gender, age, gpa

FROM user_profile

WHERE university = '山东大学'

union all/

UNION ALL 用于将两个或多个 SELECT 查询的结果集合并为一个结果集。

SELECT device_id, gender, age, gpa

FROM user_profile

WHERE gender ='male';