题目中提示不去重,所以要用UNION ALL。UNION或者where...or子句都会去重。
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'
题目中提示不去重,所以要用UNION ALL。UNION或者where...or子句都会去重。
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'