作业二
课堂练习
--1.查询全部一年级的学生信息
select s.*, '一年级' gradeid from student s where gradeid=(select gradeid from grade where gradename='一年级');
--2.查询全部二年级的学生的姓名和电话
select s.studentname,s.phone from student s where gradeid=(select gradeid from grade where gradename='二年级');
--3.查询全部一年级女同学的信息
select * from student where gradeid=(select gradeid from grade where gradename='一年级') and sex='女';
--4. 查询课时超过60的科目信息
select * from subjects where classhour>=60;
--5.查询二年级的科目名称
select * from subjects where gradeid=(select gradeid from grade where gradename='二年级');
--6.查询二年级男同学的姓名和住址
select s.studentname,s.address from student s where gradeid=(select gradeid from grade where gradename='二年级') and sex='男';
--7.查询无电子邮件的学生姓名和年级信息
select s.studentname,s.gradeid from student s,grade g where s.gradeid=g.gradeid and (email='' or email is null);
--8.查询出生日期在1992年之后的男学生姓名和年级信息
select s.studentname,g.gradename from student s,grade g where s.gradeid=g.gradeid and born>='1992-01-01' and sex='男';
select s.studentname,(select gradename from grade g where s.gradeid=g.gradeid) gradename from student s where born>='1992-01-01' and sex='男';
--9.参加了日期为2015年7月3日的“计算机基本原理”科目考试的成绩信息
select * from mark where examdate='2015-07-03' and subjectid=(select subjectid from subjects where subjectname='计算机基本原理');
--10.按照出生日期查询一年级的学生信息
select * from student where gradeid=(select gradeid from grade where gradename='一年级') order by born;
--11.按成绩由高到低的次序查询参加编号为1的科目考试信息
select * from mark where subjectid=1 order by studentscore desc;
--12.查询2015年7月1日参加“MySQL深入”考试的前2名学员成绩信息
select * from mark where examdate='2015-07-01' and subjectid=(select subjectid from subjects where subjectname='MySQL深入') order by studentscore desc limit 2;
--13.查询课时最多的科目名称及课时
select s.subjectname,s.classhour from subjects s where classhour=(select max(classhour) from subjects);
--14.查询年龄最小的学生所在的年级及姓名
select s.studentname,(select gradename from grade g where s.gradeid=g.gradeid) from student s where born=(select max(born) from student);
--15.查询考试的最低分出现在哪个科目
select subjectname from subjects where subjectid=(select subjectid from mark where studentscore=(select min(studentscore) from mark));
--16.查询学号为“s1001”的学生参加过的所有考试信息，并按照时间前后次序显示
select * from mark where studentno='s1001' order by examdate;
--17.查询年龄超过25周岁的学生信息
select * from student where year(curdate()) - year(born) >= 25;
--18.查询1月份过生日的学生信息
select * from student where month(born)=1;
--19.查询今天过生日的学生姓名及所在年级
select s.studentname,(select gradename from grade g where s.gradeid=g.gradeid) from student s where month(born)=month(now()) and day(born)=day(now());
--20.新生入学，为其分配一个Email地址，规则如下：S1+当前日期 +@bd.com
--21.查询住址为“雁塔区”的学生姓名、电话、住址
select s.studentname,s.phone,s.address from student s where address REGEXP '.*雁塔区.*';
--22.查询名称中含有“计算机”字样科目名称、学时及所属年级，并按年级由低到高显示
select s.subjectname,s.classhour,(select gradename from grade g where s.gradeid=g.gradeid) from subjects s where subjectname REGEXP '.*计算机.*' order by gradeid;
--23.查询电话中含有以“130”开头的学生姓名，住址和电话
select s.studentname,s.address,s.phone from student s where phone REGEXP '^130';
--24.查询姓“赵”的学号、姓名和住址
select s.studentno,s.studentname,s.address from student s where studentname REGEXP '^赵';
--25.统计一年级女生的总人数
select count(1) from student where gradeid=(select gradeid from grade where gradename="一年级") and sex='女';
--26.查询李四总成绩
select sum(studentscore) from mark where studentno=(select studentno from student where studentname='李四');
--27.学号为s1003的学生所有课总成绩
select sum(studentscore) from mark where studentno='s1003';
--28.学号为s1003的学生考试的平均分
select avg(studentscore) from mark where studentno='s1003';
--29.查询一年级的科目“Mysql”的最高分、最低分、平均分
select max(studentscore) '最高分',min(studentscore) '最低分',avg(studentscore) '平均分' from mark where subjectid=(select subjectid from subjects where subjectname REGEXP '.*Mysql.*' and gradeid=(select gradeid from grade where gradename='一年级'));
--30.查询每个年级的总学时数，并按照升序排列
select gradeid,sum(classhour),(select gradename from grade g where g.gradeid=s.gradeid) '年级' from subjects s group by gradeid order by sum(classhour);
--31.查询每个参加考试的学员的平均分（Group by 学号）
select studentno,avg(studentscore) from mark group by studentno;
--32.查询每门课程的平均分，并按照降序排列（group by 课程）
select subjectid,avg(studentscore),(select subjectname from subjects s where s.subjectid=m.subjectid) 'subjectname' from mark m group by subjectid order by avg(studentscore) desc;
--33.查询每个学生参加的所有考试的总分，并按照降序排列（group by 学号）
select studentno,(select studentname from student s where s.studentno=m.studentno) 'studentname',sum(studentscore) '总分' from mark m group by studentno order by '总分' desc;
--34.查询一年级的平均年龄
35、 查询每个年级西安地区的学生人数
select gradeid,count(1) '人数' from student where address REGEXP '.*西安.*' group by gradeid;
--36.查询参加考试的学生中，平均分及格的学生记录，并按照平均成绩降序排列
select * from (select studentno,avg(studentscore) 'avg' from mark group by studentno) a where avg >= 60 order by avg desc;
--37.查询参加考试至少一次考试不及格的学生学号、姓名、不及格次数
select m.studentno,(select studentname from student s where s.studentno=m.studentno),count(1) from mark m where studentscore < 60 group by studentno;
--38.查询学生姓名、所属年级名称及联系电话
select s.studentname,(select gradename from grade g where g.gradeid=s.gradeid),s.phone from student s;
--39.查询年级编号为1的科目名称、年级名称及学时
select s.subjectname,s.classhour from subjects s where gradeid=1;
--40.查询参加科目编号为1的考试的学生姓名、分数、考试日期
select (select s.studentname from student s where s.studentno=m.studentno),m.studentscore,m.examdate from mark m where subjectid=1;
--41.查询学号为s1001的学生参加的考试科目名称、分数、考试日期
select (select subjectname from subjects s where s.subjectid=m.subjectid),m.studentscore,m.examdate from mark m where studentno='s1001';
--42.查询所有科目的参考信息（某些科目可能还没有被考试过）
select * from mark where studentscore > 0;
--43.查询没有被考过的科目信息
select * from mark where studentscore = '' or studentscore is null;
查询练习
--1.查询所有记录的e_no、e_name和e_salary字段值
select e_no,e_name,e_salary from employee;
--2.查询dept_no等于10和20的所有记录
select * from employee where dept_no in (10,20);
--3.查询工资范围在800~2500之间的员工信息
select * from employee where e_salary >= 800 and e_salary <= 2500;
--4.查询部门编号为20的部门中的员工信息
select * from employee where e_no=20;
--5.查询每个部门最高工资的员工信息
select dept_no,max(e_salary) from employee group by dept_no;
--6.查询员工BLAKE所在部门和部门所在地
select (select d_name from dept d where d.d_no=e.dept_no),((select d_location from dept d where d.d_no=e.dept_no) from employee e where e.e_name='BLAKE';
--7.查询所有员工的部门和部门信息
select e.e_name,(select * from dept d where d.d_no=e.dept_no) from employee e;
--8.计算每个部门各有多少名员工
select dept_no,count(1) from employee group by dept_no;
--9.计算不同类型职工的总工资数
select depy_job,sum(e_salary) from employee group by dept_job;
--10.计算不同部门的平均工资
select depy_no,avg(e_salary) from employee group by dept_no;
--11.查询工资低于1500的员工信息
select * from employee where e_salary < 1500;
--12.将查询记录先按部门编号由高到低排列，再按员工工资由高到低排列
select * from employee order by dept_no desc,e_salary desc;
--13.查询员工姓名以字母‘A’或‘S’开头的员工的信息
select * from employee where e_name REGEXP '^A|S';
--14.查询到目前为止工龄大于等于18年的员工信息
select * from employee where year(curdate()) - year(hireDate) >= 18;
15. 计算所有女员工（‘F’）的年龄
select e.e_name,e.e_gender,year(curdate()) - year(hireDate) from employee e where e.e_gender = 'f';
--16.使用LIMIT查询从第3条记录开始到第6条记录的结果
select * from employee LIMIT 2,3;
--17.查询销售人员（SALSEMAN）的最低工资
select min(e_salary) from employee where e_job = 'SALESMAN';
--18.查询名字以字母N或者S结尾的记录
select * from employee where e_name LIKE '%N' or e_name LIKE '%S';
--19.查询在BeiJing工作的员工的姓名和职务
select e_name,e_job from employee where dept_no = (select d_no from dept where d_location = 'BeiJing');
--20.使用左连接方式查询employee和dept表
select * from employee LEFT JOIN dept ON employee.dept_no = dept.d_no;
--21.查询所有2001~2005年入职的员工的信息，查询部门编号为20和30的员工信息并使用UNION合并两个查询结果
select * from employee WHERE YEAR(hireDate) BETWEEN 2001 AND 2005 UNION SELECT * FROM employee WHERE dept_no IN(20,30);
--22.使用LIKE查询员工姓名中包含字母a的记录
SELECT * FROM employee WHERE e_name LIKE 'a%' OR e_name LIKE '%a' OR e_name LIKE '%a%';
--23.使用REGEXP查询员工姓名中包含T、C或者M这3个字母中任意1个的记录
SELECT * FROM employee WHERE e_name REGEXP '[TCM]';
