标签:student 练习 group by zoom sid style count img code
1.查询所有的课程的名称以及对应的任课老师姓名
SELECT
course.cname,
teacher.tname
FROM
teacher INNER JOIN course ON teacher.tid = course.teacher_id
cname tname
生物 张磊老师
物理 李平老师
美术 李平老师
体育 刘海燕老师
2.查询平均成绩大于80分的同学的姓名和平均成绩
SELECT
student.sname,
t1.ag
FROM
student
INNER JOIN (
SELECT
score.student_id,
AVG( score.num ) AS ag
FROM
score
GROUP BY
score.student_id
HAVING
AVG( score.num ) > 80
) AS t1 ON t1.student_id = student.sid;
sname ag
张三 82.2500
刘三 87.0000
3.查询没有报李平老师课的学生姓名
SELECT
sname
FROM
student
WHERE
student.sid NOT IN (
SELECT
student_id
FROM
score
WHERE
course_id IN ( SELECT DISTINCT cid FROM teacher INNER JOIN course ON teacher.tid = course.teacher_id WHERE tname = '李平老师' )
);
sanme
刘三
刘一
刘二
刘四
4.查询没有同时选修物理课程和体育课程的学生姓名
SELECT
sname
FROM
student
WHERE
sid IN (
SELECT
student_id
FROM
(
( SELECT * FROM score INNER JOIN course ON cid = course_id WHERE course.cname = '物理' OR course.cname = '体育' ) AS t1
)
GROUP BY
student_id
HAVING
COUNT( student_id ) = 1
);
sname
理解
钢蛋
刘三
5.查询挂科超过两门(包括两门)的学生姓名和班级
SELECT
t2.caption,
t2.sname
FROM
( ( SELECT * FROM class INNER JOIN student ON cid = class_id ) AS t2 )
WHERE
sname IN (
SELECT
sname
FROM
student
WHERE
sid IN ( SELECT student_id FROM score WHERE num < 60 GROUP BY student_id HAVING COUNT( student_id ) >= 2 )
);
caption sname
三年二班 理解
标签:student 练习 group by zoom sid style count img code
原文地址:https://www.cnblogs.com/godlover/p/12056352.html