sql综合练习题

一、表关系
年级表：class_grade
create table class_grade(gid int primary key auto_increment,gname varchar(20) not null);
insert into class_grade(gname) values('一年级'),('二年级'),('三年级');
班级表：class
create table class(cid int primary key auto_increment,caption varchar(30) not null,grade_id int not null,constraint class_name foreign key(grade_id)references class_grade(gid)on delete cascadeon update cascade);
insert into class(caption,grade_id) values('一年一班',1),('二年一班',2),('三年二班',3);学生表：student
create table student(sid int primary key auto_increment,sname varchar(20) not null,gender enum('女','男'),class_id int not null,constraint student_name foreign key(class_id)references class(cid)on delete cascadeon update cascade);
insert into student(sname,gender,class_id) values('乔丹','女',1),('艾弗森','女',1),('科比','女',2);老师表：teacher
create table teacher(tid int primary key auto_increment,tname varchar(30) not null);
insert into teacher(tname) values('张三'),('李四'),('王五');课程表：course
create table course(cid int primary key auto_increment,cname varchar(30) not null,teacher_id int not null,constraint teacher_name foreign key(teacher_id)references teacher(tid)on delete cascadeon update cascade
);
insert into course(cname,teacher_id) values('生物',1),('体育',1),('物理',2);成绩表：score
create table score(sid int primary key auto_increment,student_id int not null,course_id int not null,score int not null,foreign key(student_id) references student(sid)on delete cascadeon update cascade,foreign key(course_id) references course(cid)on delete cascadeon update cascade
);insert into score(student_id,course_id,score) values(1,1,60),(1,2,59),(2,2,99);班级任职表：teach2cls
create table teach2cls(tcid int primary key auto_increment,tid int not null,cid int not null,foreign key(tid) references teacher(tid)on delete cascadeon update cascade,foreign key(cid) references class(cid)on delete cascadeon update cascade
);insert into teach2cls(tid,cid) values(1,1),(1,2),(2,1),(3,2);2、查询学生总人数
select count(sname) 总人数 from student;3、查询’生物‘课程和’物理‘课程成绩都及格的学生id和姓名
select sid,sname
fromstudent
inner join(select student_idfrom scorewherecourse_id in (selectcidfromcoursewherecname in ('生物','物理')) and  score >= 60) as t1 on t1.student_id = student.sid;4、查询每个年级的班级数，取出班级数最多的前三个年级;
selectclass_grade.gid,class_grade.gname
fromclass_grade
inner join
(select grade_id,count(cid)fromclassgroup by grade_idorder by grade_id desclimit 3
) as t1 on t1.grade_id = class_grade.gid;5、查询平均成绩最高和最低的学生的id和姓名以及平均成绩;
selectstudent.sid,student.sname,avg_score
fromstudent
inner join(selectstudent_id,avg(score) as avg_scorefromscoregroup bystudent_idhaving avg(score) in((selectavg(score) as max_scorefromscoregroup by student_idorder byavg(score) desclimit 1),(selectavg(score) as min_scorefromscoregroup bystudent_idorder byavg(score)limit 1))) as t1 on t1.student_id = student.sid;6、查询每个年级的学生人数
select class_grade.gname,count_cid
from class_grade
inner join(selectgrade_id,count(cid) as count_cidfromclass,studentwhereclass.cid = class_idgroup by grade_id) as t1 on t1.grade_id = class_grade.gid;7、查询每位学生的学号、姓名、选课数、平均成绩;
selectstudent.sid,student.sname,course_count,avg_score
fromstudent
left join(selectstudent_id,count(course_id) as course_count,avg(score) as avg_scorefromscoregroup by student_id) as t1 on t1.student_id = student.sid;8、查询学生编号为‘2’的学生的姓名，该学生成绩最高的课程名、成绩最低的课程名及分数;
selectstudent.sname,student.sid,t1.score
from
(selectstudent_id,course_id,scorefrom scorewhere student_id = 2 and score in((selectmax(score)fromscorewhere student_id = 2),(select min(score)fromscorewhere student_id =2)) 
)as t1
inner join student on t1.student_id = student.sid
inner join course on t1.course_id = course.cid;9、查询‘李’的老师的个数和所带班级数;
selectcount(teacher.tname) as '李%个数',count(teach2cls.cid) as '班级数量'
from teacher left join teach2cls on teach2cls.tid = teacher.tid
where teacher.tname like '李%';10、查询班级数小于5年级的id和年级名;
selectgid,gname,count(cid)
fromclass_grade
inner join class on gid = grade_id
group bygid
havingcount(cid) < 5
11、查询班级信息，包括班级id、班级名称、年级、年级级别（12
为低年级，34为中年级，56为高年级）
selectclass.cid as '班级id',class.caption as '班级名称',class_grade.gid as '年级',
casewhen class_grade.gid between 1 and 2 then '低'when class_grade.gid between 3 and 4 then '中'when class_grade.gid between 5 and 6 then '高' else 0 end as '年级级别'
fromclass
left join class_grade on class_grade.gid=class.grade_id;12、查询学过“张三”老师2门课以上的同学的学号、姓名；
select sid,sname
fromstudent
where sid in 
(
selectstudent_id
fromscore
left join course on course_id = course.cid
where course.teacher_id in (    select tidfrom teacherwhere tname = '张三')
group bystudent_id
having count(course.cid)>=2
)13、查询教授课程超过2门的老师的id和姓名;
selecttid,tname
fromteacher
inner join (selectteacher_id,count(cid)fromcoursegroup byteacher_idhaving count(cid) >=2
) as t1 on t1.teacher_id = teacher.tid;14、查询学过编号‘1’课程和编号2课程的同学的学号、姓名;
selectsid,sname
fromstudent
where sid in 
(
select course_id
fromscore
group bycourse_id
havingcourse_id in (1,2)
)15、查询没有带过高年级的老师id和姓名;
selecttid,tname
fromteacher
where tid  in
(
select tid
fromteach2cls
where tid in 
(selectcid
fromclass
where grade_id in (5,6)));16、查询学过'张三'老师所教的所有课的同学的学号、姓名;
selectsid,sname
fromstudent
where sid in (selectstudent_idfromscorewhere course_id in (    selectcidfromcourseinner join teacher on teacher_id = teacher.tidwhere teacher.tname ='张三'));17、查询带过超过2个班级的老师的id和姓名;
selecttid,tname
fromteacher
where tid in (
selecttid
fromteach2cls
group bytid
havingcount(cid) >2);18、查询课程编号’2‘的成绩比课程’1‘课程低的所有同学的学号、姓名
select sid,sname
fromstudent
where sid in (
select t1.student_id
from
(selectstudent_id,scorefromscorewhere course_id =2
) as t1
inner join
(selectstudent_id,scorefromscorewhere course_id =1
) as t2 on t1.student_id = t2.student_id
where t1.score < t2.score);19、查询所带班级数最多的老师id和姓名;
selecttid,tname
fromteacher
where tid =
(selecttid
fromteach2cls
group bytid
order by count(cid) desc
limit 1);
20、查询有课程成绩小于60分的同学的学号、姓名;
selectsid,sname
fromstudent
where sid in (
selectstudent_id
fromscore
where score <60);
21、查询没有学全所有课的同学的学号、姓名;
selectsid,sname
fromstudent
where sid not in (
selectstudent_id
fromscore
group bystudent_id
havingcount(course_id) = (select count(cid) from course));
22、查询至少有一门课与学号为“1”的同学所学相同的同学的学号和姓名；
selectsid,sname
fromstudent
where sid in 
(
selectstudent_id
fromscore
where course_id in 
(selectcourse_id
fromscore
where student_id = 1));23、查询至少学过学号为“1”同学所选课程中任意一门课的其他同学学号和姓名；
selectsid,sname
fromstudent
where sid in 
(
selectstudent_id
fromscore
where course_id in 
(selectcourse_id
fromscore
where student_id = 1)
havingstudent_id !=1
);24、查询和‘2’号同学学习的课程完全相同的其它同学的学号和姓名
selectsid,sname
fromstudent
where sid in 
(selectstudent_idfromscore,(select course_id fromscorewhere student_id = 2) as t1where score.course_id = t1.course_id and score.student_id !=2group byscore.student_idhavingcount(score.course_id)=(select count(course_id) from scorewhere student_id =2)
);
25、删除学习‘张三’老师课的score表记录;
delete
fromscore
where course_id in (
select cid
fromcourse
where course.teacher_id = (
select tid
from teacher
where teacher.tname = '张三'));26、向score表中插入一些记录，这些记录要求符合以下条件：
1、没有上过编号‘2’课程的同学学号
2、插入’2‘号课程的平均成绩insert into score(student_id,course_id,score) select t1.sid,2,t2.avg from (select sid from student where sid not in (select student_id from score where course_id = 2)) as t1,(select avg(score) as avg from score group by course_id having course_id =2) as t2;27、按平均成绩从低到高显示所有学生的“语文”、“数学”、“英语”三门的课程成绩，按如下形式显示： 学生ID,语文,数学,英语,有效课程数,有效平均分；select sc.student_id as  学生ID,(select score.score from score left join course on score.course_id = course.cid where course.cname = '生物' and score.student_id = sc.student_id) as 生物,(select score.score from score left join course on score.course_id = course.cid where course.cname = '体育' and score.student_id = sc.student_id) as 体育,(select score.score from score left join course on score.course_id = course.cid where course.cname = '物理' and score.student_id = sc.student_id) as 物理,count(sc.course_id) as '有效课程数',avg(sc.score) as '有效平均分'from score as sc group by sc.student_id order by avg(sc.score);28、查询各科成绩最高和最低的分：以如下形式显示：课程ID，最高分，高低分;select course_id as "课程ID",max(score) as "最高分",min(score) as "最低分" from scoregroup by course_id29、按各科平均成绩从低到高和及格率的百分数从高到低顺序；SELECT course_id as '课程ID',AVG(score) as '平均成绩',sum(CASE WHEN score > 60 then 1 ELSE 0 END)/COUNT(1)*100 as '及格率'from scoreGROUP BY course_id ORDER BY '平均成绩' ASC,'及格率' desc;30、课程平均分从高到低显示（现实任课老师）；
SELECT score.course_id as '课程ID',avg(score) as '平均分' from score
inner join course on score.course_id = course.cid
GROUP BY course_id
ORDER BY avg(score) DESC31、查询各科成绩前三名的记录(不考虑成绩并列情况)
SELECT score.sid,score.course_id,score.score,t1.first_score,t1.sencond_score,t1.third_score from score LEFT JOIN
(SELECT sid,(select  score from score as s2 where s2.course_id=s1.course_id ORDER BY score desc LIMIT 0,1) as first_score,(select  score from score as s2 where s2.course_id=s1.course_id ORDER BY score desc LIMIT 1,1) as sencond_score,(select  score from score as s2 where s2.course_id=s1.course_id ORDER BY score desc LIMIT 2,1) as third_score
from score as s1)as t1 on score.sid = t1.sid
WHERE score.score in (t1.first_score,t1.sencond_score,t1.third_score)32、查询每门课程被选修的学生数；
SELECT score.course_id as '课程ID',count(student_id) as '学生数' from score
GROUP BY course_id33、查询选修了2门以上课程的全部学生的学号和姓名；
SELECT student.sid,student.sname from student WHERE sid in (
SELECT score.student_id from score
GROUP BY student_id
HAVING count(course_id) >=2);34、查询男生、女生的人数，按倒序排列；
select gender,count(sid) as sum from student
group by gender
order by sum desc35、查询姓“张”的学生名单；
SELECT sname from student WHERE sname like '张%'36、查询同名同姓学生名单，并统计同名人数；
SELECT sname as '名字',count(sname) as '同名人数' from student
GROUP BY sname
HAVING count(sname) >137、查询每门课程的平均成绩，结果按平均成绩升序排列，平均成绩相同时，按课程号降序排列；
select score.course_id,avg(score) as avg from score
INNER JOIN course on course.cid = course_id
GROUP BY course_id
ORDER BY avg ASC,course_id DESC;38、查询课程名称为“数学”，且分数低于60的学生姓名和分数；
SELECT sid,sname from student
where sid in (
SELECT score.student_id  from score
INNER JOIN course on course.cid = score.course_id
WHERE course.cname = '体育' and score.score <60);39、查询课程编号为“3”且课程成绩在80分以上的学生的学号和姓名；
SELECT sid,sname from  student
WHERE sid in (
SELECT score.student_id  from score
INNER JOIN course on course.cid = course_id
WHERE course_id = 3 and score.score > 80);40、求选修了课程的学生人数
select course_id as '课程ID',count(student_id) as '学生人数' from score group by course_id;41、查询选修“王五”老师所授课程的学生中，成绩最高和最低的学生姓名及其成绩；
SELECT student.sname,max(score),min(score) from score
INNER JOIN student on score.student_id = student.sid
WHERE course_id in (
SELECT cid from course
WHERE teacher_id in (
SELECT tid FROM teacher
WHERE tname = '王五'))
GROUP BY student_id
ORDER BY max(score) DESC,MIN(score) ASC
LIMIT 242、查询各个课程及相应的选修人数；
SELECT score.course_id as 'ID',course.cname as '课程',count(student_id) as '人数' from score
LEFT JOIN course on score.course_id = course.cid
GROUP BY course_id43、查询不同课程但成绩相同的学生的学号、课程号、学生成绩；
select DISTINCT s1.course_id,s2.course_id,s1.score,s2.score from score as s1, score as s2 where s1.score = s2.score and s1.course_id != s2.course_id;44、查询每门课程成绩最好的前两名学生id和姓名；
SELECT score.sid,score.course_id,score.score,t1.first_score,t1.sencond_score from score LEFT JOIN
(SELECT sid,(select  score from score as s2 where s2.course_id=s1.course_id ORDER BY score desc LIMIT 0,1) as first_score,(select  score from score as s2 where s2.course_id=s1.course_id ORDER BY score desc LIMIT 1,1) as sencond_score
from score as s1)as t1 on score.sid = t1.sid
WHERE score.score <= t1.first_score and score.score >= t1.sencond_score45、检索至少选修两门课程的学生学号；
SELECT score.student_id as '学生ID',count(course_id) as '课程ID' from score
GROUP BY student_id
HAVING count(course_id)>=246、查询没有学生选修的课程的课程号和课程名；
SELECT cid,cname from course
WHERE cid not IN(
SELECT score.course_id from score
GROUP BY score.course_id)47、查询没带过任何班级的老师id和姓名；
SELECT tid,tname from teacher
WHERE tid not in(
SELECT teach2cls.cid from teach2cls
GROUP BY teach2cls.cid)48、查询有两门以上课程超过80分的学生id及其平均成绩；
SELECT score.student_id as '学生ID',avg(score) as '平均成绩' from score
WHERE score > 30 
GROUP BY student_id
HAVING count(course_id) >=249、检索“3”课程分数小于60，按分数降序排列的同学学号；
select score.student_id from score
WHERE score < 60 and course_id = 3
ORDER BY score DESC50、删除编号为“2”的同学的“1”课程的成绩
delete from score where score.student_id = 2 and score.course_id = 1;51、查询同时选修了物理课和生物课的学生id和姓名；
SELECT sid,sname from student
WHERE sid in(
SELECT score.student_id from score
WHERE course_id in (
SELECT cid from course
WHERE course.cname in ('生物','物理'))
GROUP BY student_id
HAVING count(course_id) =2)

 

转载于:https://www.cnblogs.com/yjiu1990/p/9263395.html

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