SQL练习题-30道
sql查询30题
使用方法：我用的数据库是 mysql数据库Webyog-SQLyog-Ultimate12.0.8.0l,大家练习时应当自己准备数据，自己先思考，切勿急躁翻答案！否则效果减半，做完这些，恭喜你，你的 SQL 就算过关了。
我的首页： https://www.cnblogs.com/wan-ge1212/
准备数据 ： 测试表格
-数据库文件：
–-1.学生表
Student(s_id,s_name,s_birth,s_sex) –-学生编号,学生姓名, 出生年月,学生性别
–-2.课程表
Course(c_id,c_name,t_id) ––课程编号, 课程名称, 教师编号
–-3.教师表
Teacher(t_id,t_name) –教师编号,教师姓名
–-4.成绩表
Score(s_id,c_id,s_score) –-学生编号,课程编号,分数
---------------------
--建表
–-1.学生表
CREATE TABLE `Student`(
`s_id` VARCHAR(20),
`s_name` VARCHAR(20) NOT NULL DEFAULT '',
`s_birth` VARCHAR(20) NOT NULL DEFAULT '',
`s_sex` VARCHAR(10) NOT NULL DEFAULT '',
PRIMARY KEY(`s_id`)
);
--课程表
CREATE TABLE `Course`(
`c_id` VARCHAR(20),
`c_name` VARCHAR(20) NOT NULL DEFAULT '',
`t_id` VARCHAR(20) NOT NULL,
PRIMARY KEY(`c_id`)
);
--教师表
CREATE TABLE `Teacher`(
`t_id` VARCHAR(20),
`t_name` VARCHAR(20) NOT NULL DEFAULT '',
PRIMARY KEY(`t_id`)
);
--成绩表
CREATE TABLE `Score`(
`s_id` VARCHAR(20),
`c_id` VARCHAR(20),
`s_score` INT(3),
PRIMARY KEY(`s_id`,`c_id`)
);
--插入学生表测试数据
insert into Student values('01' , '赵雷' , '1990-01-01' , '男');
insert into Student values('02' , '钱电' , '1990-12-21' , '男');
insert into Student values('03' , '孙风' , '1990-05-20' , '男');
insert into Student values('04' , '李云' , '1990-08-06' , '男');
insert into Student values('05' , '周梅' , '1991-12-01' , '女');
insert into Student values('06' , '吴兰' , '1992-03-01' , '女');
insert into Student values('07' , '郑竹' , '1989-07-01' , '女');
insert into Student values('08' , '王菊' , '1990-01-20' , '女');
--课程表测试数据
insert into Course values('01' , '语文' , '02');
insert into Course values('02' , '数学' , '01');
insert into Course values('03' , '英语' , '03');
--教师表测试数据
insert into Teacher values('01' , '张三');
insert into Teacher values('02' , '李四');
insert into Teacher values('03' , '王五');
--成绩表测试数据
insert into Score values('01' , '01' , 80);
insert into Score values('01' , '02' , 90);
insert into Score values('01' , '03' , 99);
insert into Score values('02' , '01' , 70);
insert into Score values('02' , '02' , 60);
insert into Score values('02' , '03' , 80);
insert into Score values('03' , '01' , 80);
insert into Score values('03' , '02' , 80);
insert into Score values('03' , '03' , 80);
insert into Score values('04' , '01' , 50);
insert into Score values('04' , '02' , 30);
insert into Score values('04' , '03' , 20);
insert into Score values('05' , '01' , 76);
insert into Score values('05' , '02' , 87);
insert into Score values('06' , '01' , 31);
insert into Score values('06' , '03' , 34);
insert into Score values('07' , '02' , 89);
insert into Score values('07' , '03' , 98);
---------------------
-- 1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数
SELECT A.s_id,A.s_score
FROM (SELECT * FROM score WHERE c_id=1) A,
(SELECT * FROM score WHERE c_id=2 ) B
WHERE A.s_id=B.s_id
AND A.s_score>B.s_score;
-- 2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数
SELECT A.s_id,A.s_score
FROM (SELECT * FROM score WHERE c_id=1) A,
(SELECT * FROM score WHERE c_id=2 ) B
WHERE A.s_id=B.s_id
AND A.s_score>B.s_score;
-- 3、查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩
SELECT A.s_id,B.s_name,AVG(A.s_score)
FROM Score A,Student B
WHERE A.s_id=B.s_id
GROUP BY A.s_id,B.s_name
HAVING AVG(A.s_score)>=60;
-- 4、查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩(包括有成绩的和无成绩的)
SELECT A.s_id,B.s_name,AVG(A.s_score)
FROM Score A,Student B
WHERE A.s_id=B.s_id
GROUP BY A.s_id,B.s_name
HAVING AVG(A.s_score)<60
or AVG(A.s_score) is null;
-- 5、查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩
SELECT E.s_id,E.s_name,COUNT(C.c_id)OVER(PARTITION BY C.s_id,E.s_name),
SUM(C.s_score)OVER(PARTITION BY C.s_id,C.c_id)
FROM Student E,Score C
WHERE E.s_id=C.s_id;
-- 6、查询"李"姓老师的数量
SELECT COUNT(t_id)
FROM Teacher
WHERE t_name LIKE '李%';
-- 7、查询学过"张三"老师授课的同学的信息
SELECT S.*
FROM Student S,Score C
WHERE S.s_id=C.s_id AND C.c_id IN
(SELECT E.c_id FROM Course E,Teacher T
WHERE E.c_name=T.t_name AND T.t_name='张三');
-- 8、查询没学过"张三"老师授课的同学的信息
SELECT S.*
FROM Student S WHERE NOT EXISTS
(SELECT s_id FROM Score X,Course C,Teacher T
WHERE X.c_id=C.c_id AND C.t_id=T.t_id AND T.t_name='张三' AND S.s_id=X.s_id)
-- 9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息
SELECT DISTINCT S.* FROM Score C,Student S
WHERE S.S_ID=C.S_ID AND C_ID=1
UNION
SELECT DISTINCT S.* FROM Score C,Student S
WHERE S.S_ID=C.S_ID AND C_ID=2
-- 10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息
SELECT DISTINCT S.* FROM Score C,Student S
WHERE S.S_ID=C.S_ID AND C_ID=1
UNION
SELECT DISTINCT S.* FROM Student S
WHERE NOT EXISTS
(SELECT s_id FROM Score C WHERE C_ID=2 AND S.s_id=C.s_id)
-- 11、查询没有学全所有课程的同学的信息
SELECT S.* FROM Student S,Score C
WHERE S.S_ID=C.S_ID
GROUP BY S.S_ID,S.s_name
HAVING COUNT(C.C_ID)!=(SELECT COUNT(C_ID)FROM COURSE);
-- 12、查询至少有一门课与学号为"01"的同学所学相同的同学的信息
SELECT DISTINCT S.* FROM STUDENT S,SCORE C
WHERE S.S_ID!=1 AND C.C_ID IN
(SELECT C_ID FROM SCORE WHERE S_ID=1);
-- 13、查询和"01"号的同学学习的课程完全相同的其他同学的信息
SELECT DISTINCT S.*
FROM STUDENT S,SCORE C
WHERE S.S_ID=C.S_ID AND C.S_ID!=1
GROUP BY S.S_ID,S.S_NAME
HAVING COUNT( C.C_ID)=
(SELECT COUNT(C_ID) FROM SCORE WHERE S_ID=1);
-- 14、查询没学过"张三"老师讲授的任一门课程的学生姓名
SELECT S_ID,S_NAME FROM STUDENT WHERE S_ID NOT IN
(SELECT C.S_ID
FROM SCORE C,COURSE E,TEACHER T
WHERE C.C_ID=E.C_ID AND E.T_ID=T.T_ID AND T.T_NAME='张三' );
-- 15、查询两门及其以上不及格课程的同学的学号，姓名及其平均成绩
select s_name,avg(s_score)
from Student S,Score sc
where s.s_id=sc.s_id and s_score<60
group by s_name
having count(s_score)>=2
-- 16、检索"01"课程分数小于60，按分数降序排列的学生信息
SELECT S_ID FROM SCORE
WHERE C_ID=1 AND S_SCORE<60
ORDER BY S_SCORE DESC;
-- 17、按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩
select distinct A.c_id,c_name,最高分,最低分,平均分,及格率,中等率,优良率,优秀率
from Score A
left join Course on A.c_id=Course.c_id
left join (select c_id,MAX(s_score) 最高分,
MIN(s_score) 最低分,AVG(s_score) 平均分
from Score group by c_id)B on A.c_id=B.c_id
left join (select c_id,(convert(decimal(5,2),
(sum(case when s_score>=60 then 1 else 0 end)*1.00)/COUNT(*))*100) 及格率
from Score group by c_id)C on A.c_id=C.c_id
left join (select c_id,(convert(decimal(5,2),
(sum(case when s_score >=70 and s_score<80 then 1 else 0 end)*1.00)/COUNT(*))*100) 中等率
from Score group by c_id)D on A.c_id=D.c_id
left join (select c_id,(convert(decimal(5,2),
(sum(case when s_score >=80 and s_score<90 then 1 else 0 end)*1.00)/COUNT(*))*100) 优良率
from Score group by c_id)E on A.c_id=E.c_id
left join (select c_id,(convert(decimal(5,2),
(sum(case when s_score >=90 then 1 else 0 end)*1.00)/COUNT(*))*100) 优秀率
from Score group by c_id)F on A.c_id=F.c_id
-- 18、查询各科成绩最高分、最低分和平均分：以如下形式显示：课程ID，课程name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率及格为>=60，中等为：70-80，优良为：80-90，优秀为：>=90
select *,RANK()over(order by s_score desc)排名 from Score
-- 19、查询下月过生日的学生 (sql server)
select s.* from Student s
where to_char(s.s_birth, 'mm')=to_char(add_months(trunc(sysdate),1),'mm')
-- 20、查询本月过生日的学生 (sql server)
select s.* from Student s
where to_char(s.s_birth, 'mm') = to_char(sysdate,'mm')
-- 21、查询下周过生日的学生 (sql server)
select s.* from student s
where to_char(s.s_birth, 'mmdd') between
to_char(trunc(sysdate, 'iw')+7, 'mmdd') and
to_char(trunc(sysdate, 'iw') + 13, 'mmdd')
-- 22、查询本周过生日的学生 (sql server)
select st.* from student s
where to_char(s.s_birth, 'mmdd') between
to_char(trunc(sysdate, 'iw'), 'mmdd') and
to_char(trunc(sysdate, 'iw') + 6, 'mmdd')
-- 23、查询各学生的年龄,按照出生日期来算，当前月日 < 出生年月的月日则，年龄减一 (sql server)
select s.*, (to_char(sysdate, 'yyyy') - to_char(s.s_birth, 'yyyy')) "年龄" from student s
-- 24、查询选修了全部课程的学生信息
SELECT S.* FROM STUDENT S,SCORE C
WHERE S.S_ID=C.S_ID
GROUP BY S.S_ID,S.s_name
HAVING COUNT(C.C_ID) IN (SELECT COUNT(C_ID)FROM COURSE);
-- 25、检索至少选修两门课程的学生学号
SELECT S_ID,COUNT(C_ID)FROM SCORE GROUP BY S_ID HAVING COUNT(C_ID)>2;
-- 26、查询每门功成绩最好的前两名
select c_id,COUNT(s_id)选修人数 from Score
group by c_id
having COUNT(s_id)>5
order by 选修人数 desc,c_id
-- 27、查询选修"张三"老师所授课程的学生中，成绩最高的学生信息及其成绩
SELECT S.S_ID,C.S_SCORE
FROM STUDENT S,SCORE C,COURSE E,TEACHER T
WHERE S.S_ID=C.S_ID AND C.C_ID=E.C_ID AND E.T_ID=T.T_ID AND T.T_NAME='张三'
AND C.S_SCORE=(SELECT MAX(S_SCORE)FROM SCORE WHERE C_ID=C.C_ID );
-- 28、查询所有学生的课程及分数情况
select a.s_id,a.s_name,b.s_id,c.c_name,b.s_score
from student a,Score b,Course c
where a.s_id=b.s_id and b.c_id=c.c_id;
-- 29、查询平均成绩大于等于85的所有学生的学号、姓名和平均成绩
SELECT S.S_ID,S_NAME,AVG(S_SCORE) FROM STUDENT S,SCORE C
WHERE S.S_ID=C.S_ID GROUP BY S.S_ID,S_NAME
HAVING AVG(S_SCORE)>=85;
-- 30、查询同名同性学生名单，并统计同名人数
select s_name,count(s_name) from student
group by s_name having count(s_name)>1 ;
