两个给定的表:
问题:选择费用最高的activity和在其中注册的学生姓名。
结果应该是:activity栏(高尔夫)和学生栏(马克安东尼)。 在这种情况下,只有一个学生注册,但如果有更多的学生注册,我想说明一个案例。
我试过各种解决办法,但似乎都做不对。
谢谢你的建议。
编辑:我看到我被否决了,我不想展示我尝试了什么,因为我认为它离题了,但这里有一些:
SELECT s.Student, a.Activity from Activities as a inner join Students as s
ON a.ID = s.ID where a.Cost = (select max(a.Cost))
SELECT s.Student, a.cost, a.Activity from Activities as a inner join Students `as s ON a.ID = s.ID`
group by s.Student having a.cost = max(a.cost)
以下查询有效。
但请下次不要使用图像,你也应该看看标准化
CREATE TABLE activity (
`ID` INTEGER,
`Activity` VARCHAR(8),
`Cost` INTEGER
);
INSERT INTO activity
(`ID`, `Activity`, `Cost`)
VALUES
('84', 'Swimming', '17'),
('84', 'Tennis', '36'),
('100', 'Squash', '40'),
('100', 'Swimming', '17'),
('182', 'Tennis', '36'),
('219', 'Golf', '47'),
('219', 'Swimming', '15'),
('219', 'Squash', '40');
CREATE TABLE students (
`Student` VARCHAR(11),
`ID` INTEGER
);
INSERT INTO students
(`Student`, `ID`)
VALUES
('John Smith', '84'),
('Jane Bloggs', '100'),
('John Smith', '182'),
('Mark Antor', '219');
SELECT Student,Activity
FROM students s INNER JOIN (
SELECT id,Activity FROm activity WHERE Cost = (SELECT MAX(Cost) FROM activity)) a ON s.ID = a.id
Student | Activity :--------- | :------- Mark Antor | Golf
db<;>此处小提琴