我整理的必刷SQL经典题目
SQL语句在工作与面试时都必不可少，下面我整理了20道题目供大家练习，常见的使用方法和开窗函数都有考察，来测测你的sql技能是否过关。
一、创建表
共有4个表，分别是学生信息表、课程表、老师信息表和成绩表。
1 学生信息表
--建表语句
CREATE TABLE Student (
SID VARCHAR (10),
Sname VARCHAR (10),
Sage datetime,
Ssex VARCHAR (10)
)
--插入测试数据
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')
2 课程表
--建表语句
CREATE TABLE Course (
CID VARCHAR (10),
Cname VARCHAR (10),
TID VARCHAR (10)
)
--插入测试数据
INSERT INTO Course VALUES('01' , '语文' , '02')
INSERT INTO Course VALUES('02' , '数学' , '01')
INSERT INTO Course VALUES('03' , '英语' , '03')
3 老师信息表
--建表语句
CREATE TABLE Teacher (
TID VARCHAR (10),
Tname varchar (10)
)
--插入测试数据
INSERT INTO Teacher VALUES('01' , '张三')
INSERT INTO Teacher VALUES('02' , '李四')
INSERT INTO Teacher VALUES('03' , '王五')
4 成绩表
--建表语句
CREATE TABLE SC (
SID VARCHAR (10),
CID VARCHAR (10),
score int (5)
)
--插入测试数据
INSERT INTO SC VALUES('01' , '01' , 80)
INSERT INTO SC VALUES('01' , '02' , 90)
INSERT INTO SC VALUES('01' , '03' , 99)
INSERT INTO SC VALUES('02' , '01' , 70)
INSERT INTO SC VALUES('02' , '02' , 60)
INSERT INTO SC VALUES('02' , '03' , 80)
INSERT INTO SC VALUES('03' , '01' , 80)
INSERT INTO SC VALUES('03' , '02' , 80)
INSERT INTO SC VALUES('03' , '03' , 80)
INSERT INTO SC VALUES('04' , '01' , 50)
INSERT INTO SC VALUES('04' , '02' , 30)
INSERT INTO SC VALUES('04' , '03' , 20)
INSERT INTO SC VALUES('05' , '01' , 76)
INSERT INTO SC VALUES('05' , '02' , 87)
INSERT INTO SC VALUES('06' , '01' , 31)
INSERT INTO SC VALUES('06' , '03' , 34)
INSERT INTO SC VALUES('07' , '02' , 89)
INSERT INTO SC VALUES('07' , '03' , 98)
二、练习题
Q1：查询「李」姓老师的数量
SELECT
count( * ) 李老师数据
FROM
teacher
WHERE
Tname LIKE '李%'
Q2：查询存在成绩的学生信息
--方法1：
SELECT DISTINCT
s.*
FROM
sc g
JOIN student s ON g.sid = s.sid
WHERE
g.score IS NOT NULL
--方法2：
SELECT
*
FROM
student
WHERE
sid IN ( SELECT sid FROM sc WHERE sc.score IS NOT NULL )
Q3：查询不存在"01"课程但存在"02"课程的情况
SELECT
*
FROM
sc
WHERE
cid = '02'
AND SID NOT IN ( SELECT SID FROM SC WHERE CID = '01' )
Q4：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.*,
B.score
FROM
Student A
JOIN ( SELECT * FROM SC WHERE CID = '01' ) B ON A.SID = B.SID
JOIN ( SELECT * FROM SC WHERE CID = '02' ) C ON C.SID = B.SID
WHERE
B.score > C.score
Q5：查询存在"01"课程但可能不存在"02"课程的情况(不存在时显示为null)
SELECT
*
FROM
student s
JOIN ( SELECT * FROM sc WHERE cid = '01' ) g1 ON s.SID = g1.sid
LEFT JOIN ( SELECT * FROM sc WHERE cid = '02' ) g2 ON s.SID = g2.sid
Q6：查询学过「张三」老师授课的同学的信息
SELECT
s.*,
T.Tname
FROM
student s
JOIN SC G ON S.SID = G.SID
JOIN course C ON G.CID = C.CID
JOIN teacher T ON C.TID = T.TID
WHERE
TNAME = '张三'
Q7：查询没学过"张三"老师讲授的任一门课程的学生姓名
SELECT
s.Sname
FROM
student s
WHERE
sid NOT IN (
SELECT
g.sid
FROM
sc g
JOIN course c ON g.cid = c.cid
JOIN teacher t ON t.tid = c.tid
WHERE
t.tname = '张三'
)
Q8：查询任何一门课程成绩在 70 分以上的姓名、课程名称和分数
SELECT
c.Sname,
c.score,
d.Cname
FROM
(
SELECT
a.sid,
a.Sname,
b.score,
b.cid
FROM
student a
JOIN ( SELECT sid, cid, score FROM sc WHERE score > 70 ) b ON a.sid = b.sid
) c
JOIN course d ON d.cid = c.cid
Q9：查询各科成绩最高分、最低分和平均分
SELECT
cid,
max( SCORE ),
min( score ),
AVG( SCORE )
FROM
sc
GROUP BY
CID
Q10：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(没成绩的显示为null)
SELECT
s.SID,
s.Sname,
sum( g.score ),
COUNT( g.cid )
FROM
student s
LEFT JOIN sc g ON s.sid = g.sid
GROUP BY
s.SID
Q11：查询没有学全所有课程的同学的信息
SELECT
s.*,
count( g.cid )
FROM
student s
JOIN sc g ON s.sid = g.SID
GROUP BY
s.sid
HAVING
count( g.cid ) < ( SELECT count( * ) FROM course)
Q12：检索"01"课程分数小于 60，按分数降序排列的学生信息
SELECT
s.*,
g.score
FROM
student s
RIGHT JOIN ( SELECT sid, score FROM sc WHERE score < 60 AND cid = '01' ) g ON s.sid = g.SID
ORDER BY
g.score DESC
Q13：查询出只选修两门课程的学生学号和姓名
SELECT
sid,
sname
FROM
student
WHERE
sid IN ( SELECT sid FROM sc GROUP BY sid HAVING count( CID ) = 2 )
Q14：查询平均成绩大于等于85分的所有学生的学号、姓名和平均成绩
SELECT
a.*,
b.平均成绩
FROM
student a
JOIN ( SELECT sid, avg( score ) 平均成绩 FROM sc GROUP BY sid HAVING avg( score ) >= 85 ) b ON a.sid = b.sid
Q15：查询课程名称为「数学」，且分数低于60的学生姓名和分数
SELECT
*
FROM
student a
JOIN (
SELECT
g.sid,
c.Cname,
g.score
FROM
sc g
JOIN course c ON g.cid = c.cid
WHERE
c.Cname = '数学'
AND g.score < 60
) b ON a.SID = b.SId
Q16：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
SID,
avg( score ),
MAX( CASE WHEN CID = '01' THEN score ELSE 0 END ) '01',
MAX( CASE WHEN CID = '02' THEN score ELSE 0 END ) '02',
MAX( CASE WHEN CID = '03' THEN score ELSE 0 END ) '03'
FROM
sc
GROUP BY
SID
ORDER BY
avg( score ) DESC
Q17：展示每位同学的各科成绩，并将各科成绩排名
SELECT
*,
RANK ( ) over ( PARTITION BY sid ORDER BY score DESC ) 排名
FROM
SC
Q18：查询学生的总成绩，并进行排名
SELECT
sid,
a.总成绩,
rank ( ) over ( ORDER BY a.总成绩 DESC ) 总成绩排名
FROM
( SELECT SID, sum( score ) 总成绩 FROM sc GROUP BY sid ) a
Q19：查询各科成绩前三名的记录
SELECT
*
FROM
( SELECT CID, score, RANK ( ) OVER ( PARTITION BY CID ORDER BY SCORE DESC ) 排名 FROM SC ) a
WHERE
a.排名 <4
Q20：查询每门功课成绩最好的前两名文章来源：https://www.toymoban.com/news/detail-434782.html
SELECT
a.*
FROM
( SELECT cid, score, rank ( ) over ( PARTITION BY cid ORDER BY score DESC ) 排名 FROM sc ) a
WHERE
a.排名 <= 2
我整理的必刷SQL经典题目文章来源地址https://www.toymoban.com/news/detail-434782.html
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