1)     创建student和score表

2)     为student表和score表增加记录

3)     查询student表的所有记录

SELECT * from student

4)     查询student表的第2条到4条记录

SELECT * FROM student LIMIT 1,3

5)     从student表查询所有学生的学号(id)、姓名(name)和院系(department)的信息

SELECT id,name,department from student

6)     从student表中查询计算机系和英语系的学生的信息

select * from student where department in ('计算机系','英语系')

7)     从student表中查询年龄18~22岁的学生信息

select * from student where ((2017 - birth) + 1) >=28and ((2017 - birth) + 1) <= 32

8)     从student表中查询每个院系有多少人

select department,COUNT(*) fromstudent GROUP BY department

9)     从score表中查询每个科目的最高分

select c_name,max(grade) from score GROUP BY c_name

10)  查询李四的考试科目(c_name)和考试成绩(grade)

select * from score as s LEFT JOIN student as st ONs.stu_id = st.id where name = '李四'

11)  用连接的方式查询所有学生的信息和考试信息

select * fromscore as s LEFT JOIN student as st ON s.stu_id = st.id

12)  计算每个学生的总成绩

select name,SUM(grade) from score LEFT JOIN student ONstu_id = student.id GROUP BY name

13)  计算每个考试科目的平均成绩

select c_name, AVG(grade) from score GROUP BY c_name

14)  查询计算机成绩低于95的学生信息

select name from score LEFT JOIN student on score.stu_id =student.id GROUP BY c_name HAVING AVG(grade) < 95

15)  查询同时参加计算机和英语考试的学生的信息

select name from (select * from score where c_name = '计算机') as s inner JOIN (select * from score where c_name = '英语') as st on s.stu_id = st.stu_id INNER JOIN student on s.stu_id =student.id

16)  将计算机考试成绩按从高到低进行排序

select * from score where c_name = '计算机' ORDER BY grade desc

17)  从student表和score表中查询出学生的学号，然后合并查询结果

select * from score as s INNER JOIN student as st ONs.stu_id = st.id

18)  查询姓张或者姓王的同学的姓名、院系和考试科目及成绩

select * from score as s INNER JOIN student as st ONs.stu_id = st.id where name like '张%' or name like '王%'

19)  查询都是湖南的学生的姓名、年龄、院系和考试科目及成绩

select * from score as s INNER JOIN student as st ON s.stu_id= st.id where address like '湖南%'