mysql学习总结练习

网上查找的练习进行复习sql；虽然都不难，但是对打基础是很有好处的，在明白的基础上可以进一步做分析，来研究一下各种解法的优劣，甚至进行简单的优化

建表初始化：（一段一段执行）

CREATE TABLE STUDENT
(SNO VARCHAR(3) NOT NULL,
SNAME VARCHAR(4) NOT NULL,
SSEX VARCHAR(2) NOT NULL,
SBIRTHDAY DATETIME,
CLASS VARCHAR(5))
 
CREATE TABLE COURSE
(CNO VARCHAR(5) NOT NULL,
CNAME VARCHAR(10) NOT NULL,
TNO VARCHAR(10) NOT NULL)
 
CREATE TABLE SCORE
(SNO VARCHAR(3) NOT NULL,
CNO VARCHAR(5) NOT NULL,
DEGREE NUMERIC(10, 1) NOT NULL)
 
CREATE TABLE TEACHER
(TNO VARCHAR(3) NOT NULL,
TNAME VARCHAR(4) NOT NULL, TSEX VARCHAR(2) NOT NULL,
TBIRTHDAY DATE NOT NULL, PROF VARCHAR(6),
DEPART VARCHAR(10) NOT NULL)


INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (108 ,'曾华'
,'男' ,'1977-09-01',95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (105 ,'匡明'
,'男' ,'1975-10-02',95031);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (107 ,'王丽'
,'女' ,'1976-01-23',95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (101 ,'李军'
,'男' ,'1976-02-20',95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (109 ,'王芳'
,'女' ,'1975-02-10',95031);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (103 ,'陆君'
,'男' ,'1974-06-03',95031);
 
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-105' ,'计算机导论',825);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-245' ,'操作系统' ,804);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('6-166' ,'数据电路' ,856);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('9-888' ,'高等数学' ,100);
 
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (103,'3-245',86);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (105,'3-245',75);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (109,'3-245',68);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (103,'3-105',92);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (105,'3-105',88);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (109,'3-105',76);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (101,'3-105',64);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (107,'3-105',91);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (108,'3-105',78);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (101,'6-166',85);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (107,'6-106',79);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (108,'6-166',81);
 
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (804,'李诚','男','1958-12-02','副教授','计算机系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (856,'张旭','男','1969-03-12','讲师','电子工程系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (825,'王萍','女','1972-05-05','助教','计算机系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (831,'刘冰','女','1977-08-14','助教','电子工程系');

题目&答案

1、 查询Student表中的所有记录的Sname、Ssex和Class列。

SELECT Sname,Ssex,Class FROM Student
2、 查询教师所有的单位即不重复的Depart列。
SELECT DISTINCT Depart FROM teacher 
3、 查询Student表的所有记录。
SELECT * FROM Student
4、 查询Score表中成绩在60到80之间的所有记录。
SELECT  * FROM Score WHERE DEGREE BETWEEN(60,80)
5、 查询Score表中成绩为85，86或88的记录。
SELECT * FROM Score WHERE DEGREE IN(85,86,88)
6、 查询Student表中“95031”班或性别为“女”的同学记录。
SELECT * FROM student WHERE CLASS ='95031' OR SSEX='女'
7、 以Class降序查询Student表的所有记录。
SELECT * FROM student ORDER BY ClASS DESC
8、 以Cno升序、Degree降序查询Score表的所有记录。
SELECT * FROM SCORE ORDER BY Cno ASC,Degree DESC
9、 查询“95031”班的学生人数。
SELECT COUNT(*) FROM student WHERE CLASS='95031' 
10、查询Score表中的最高分的学生学号和课程号。
SELECT SNO,CNO 
FROM score 
WHERE DEGREE= (SELECT MAX(DEGREE) FROM score) 
11、查询‘3-105’号课程的平均分。
SELECT AVG(DEGREE) FROM score WHERE CNO='3-105'
12、查询Score表中至少有5名学生选修的并以3开头的课程的平均分数。
SELECT AVG(DEGREE) FROM score 
WHERE CNO LIKE "3%" GROUP BY cno HAVING COUNT(sno)>5
13、查询最低分大于70，最高分小于90的Sno列。
SELECT * FROM score GROUP BY sno HAVING MAX(degree)<=90 AND MIN(degree)>=70
14、查询所有学生的Sname、Cno和Degree列。
SELECT s.Sname ,sc.Cno,sc.Degree FROM student s,score sc WHERE s.sno= sc.sno
15、查询所有学生的Sno、Cname和Degree列。
SELECT sno,Cname,Degree 
FROM score s, course c 
WHERE s.cno =c.cno 


SELECT A.CNAME, B.SNO,B.DEGREE FROM COURSE AS A JOIN SCORE AS B ON A.CNO=B.CNO ;


16、查询所有学生的Sname、Cname和Degree列。
SELECT st.sname,c.cname,sc.Degree 
FROM student st JOIN (score sc , course c)
WHERE st.sno =sc.sno AND sc.cno = c.cno  
17、查询“95033”班所选课程的平均分。
SELECT * FROM course WHERE class ='95033'
SELECT AVG(degree) 
FROM student st JOIN (score sc , course c)
WHERE st.class ='95033'
18、假设使用如下命令建立了一个grade表：
CREATE TABLE grade(low  number(3,0),upp   number(3),rank   CHAR(1));
INSERT INTO grade VALUES(90,100,’A’);
INSERT INTO grade VALUES(80,89,’B’);
INSERT INTO grade VALUES(70,79,’C’);
INSERT INTO grade VALUES(60,69,’D’);
INSERT INTO grade VALUES(0,59,’E’);
COMMIT;
现查询所有同学的Sno、Cno和rank列。
19、查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。
SELECT degree FROM score WHERE cno = '3-105' 
SELECT degree FROM score WHERE sno ='109'
SELECT s.* FROM score s JOIN score ss WHERE s.cno='3-105' AND s.degree>ss.degree AND ss.sno='109' AND ss.cno='3-105'
SELECT A.* FROM SCORE A JOIN SCORE B WHERE A.CNO='3-105' AND A.DEGREE>B.DEGREE AND
B.SNO='109' AND B.CNO='3-105';


20、查询score中选学一门以上课程的同学中分数为非最高分成绩的记录。
SELECT * FROM score WHERE degree<(SELECT MAX(degree) FROM score) GROUP BY sno HAVING COUNT(sno)>1 ORDER BY degree DESC
21、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。
SELECT a.* FROM score a WHERE a.degree>ALL(SELECT degree FROM score b WHERE b.sno='109' AND b.cno='3-105') ORDER BY degree DESC
SELECT degree FROM score b WHERE b.sno='109' AND b.cno='3-105' -- 76
22、查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。
SELECT sno,sname,SBIRTHDAY FROM student WHERE SBIRTHDAY = (SELECT SBIRTHDAY FROM student WHERE sno='108')
23、查询“张旭“教师任课的学生成绩。
SELECT degree FROM student s,teacher t,score sc,course c 
WHERE c.tno = t.tno AND c.cno = sc.cno AND sc.sno=s.sno AND  t.tname='张旭'

SELECT A.SNO,A.DEGREE FROM SCORE A JOIN (TEACHER B,COURSE C)
ON A.CNO=C.CNO AND B.TNO=C.TNO
WHERE B.TNAME='张旭';

24、查询选修某课程的同学人数多于5人的教师姓名。
SELECT t.tname FROM teacher t JOIN (score s ,course c) ON (s.cno=c.cno  AND c.tno =t.tno) GROUP BY s.cno HAVING COUNT(s.cno)>5

SELECT A.TNAME FROM TEACHER A JOIN (COURSE B, SCORE C) ON (A.TNO=B.TNO AND B.CNO=C.CNO)
GROUP BY C.CNO HAVING COUNT(C.CNO)>5;
SELECT tname FROM teacher WHERE tno IN(SELECT x.tno FROM course X,score Y WHERE
x.cno=y.cno GROUP BY x.tno HAVING COUNT(x.tno)>5);

25、查询95033班和95031班全体学生的记录。
SELECT * FROM course c JOIN (score sc ,student st,teacher t ) ON (c.cno=sc.cno AND sc.sno = st.sno  AND t.tno =c.tno)
WHERE st.class='95033' OR st.class ='95031' ORDER BY class DESC
26、查询存在有85分以上成绩的课程Cno.
SELECT c.cno ,c.cname FROM course c WHERE cno IN (SELECT cno FROM score WHERE DEGREE>85)
SELECT DISTINCT cno FROM score WHERE degree IN (SELECT degree FROM score WHERE degree>85);
27、查询出“计算机系“教师所教课程的成绩表。
SELECT sc.degree FROM score sc WHERE cno IN (SELECT c.cno FROM course c ,teacher t WHERE c.tno=t.tno AND t.depart='计算机系')
SELECT * FROM score WHERE cno IN (SELECT a.cno FROM course a JOIN teacher b ON
a.tno=b.tno AND b.depart='计算机系');


28、查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。
SELECT tname ,prof FROM teacher WHERE DEPART='计算机系' AND prof NOT IN (SELECT prof FROM teacher WHERE DEPART ='电子工程系')


29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
SELECT cno,sno,degree 
FROM score  a 
WHERE (SELECT degree FROM score b WHERE b.cno='3-105' AND a.sno =b.sno) >=
(SELECT degree FROM score c WHERE c.cno='3-245' AND a.sno =c.sno) ORDER BY degree DESC


SELECT Cno,Sno,Degree FROM Score a WHERE (SELECT Degree FROM Score b WHERE Cno='3-105' AND b.Sno=a.Sno)>=(SELECT Degree FROM Score c WHERE Cno='3-245' AND c.Sno=a.Sno) ORDER BY Degree DESC




30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.


31、查询所有教师和同学的NAME、sex和birthday.
SELECT sname AS NAME,ssex AS sex ,SBIRTHDAY AS birthday FROM student 
UNION
SELECT tname AS NAME,tsex AS sex ,tBIRTHDAY AS birthday FROM teacher   
32、查询所有“女”教师和“女”同学的NAME、sex和birthday.
SELECT sname AS NAME,ssex AS sex ,SBIRTHDAY AS birthday FROM student WHERE ssex ='女'
UNION
SELECT tname AS NAME,tsex AS sex ,tBIRTHDAY AS birthday FROM teacher   WHERE tsex ='女'
33、查询成绩比该课程平均成绩低的同学的成绩表。
SELECT sno, degree FROM score WHERE degree<=(SELECT AVG(degree) FROM score)
34、查询所有任课教师的Tname和Depart.
SELECT tname,DEPART FROM teacher t,course c WHERE  t.tno =c.tno


35  查询所有未讲课的教师的Tname和Depart. 
SELECT tname,DEPART FROM teacher t WHERE NOT EXISTS (SELECT tno FROM course c WHERE t.tno=c.tno)


36、查询至少有2名男生的班号。


SELECT class FROM student WHERE ssex='男' GROUP BY class HAVING COUNT(ssex)>=2
37、查询Student表中不姓“王”的同学记录。
SELECT * FROM student WHERE sname NOT LIKE '王%'
38、查询Student表中每个学生的姓名和年龄。
  SELECT  sname ,(YEAR(NOW())-YEAR(SBIRTHDAY)) AS age FROM student
  
39、查询Student表中最大和最小的Sbirthday日期值。
SELECT sname,sbirthday AS THEMAX FROM student WHERE sbirthday =(SELECT MIN(SBIRTHDAY)


FROM student)
UNION
SELECT sname,sbirthday AS THEMIN FROM student WHERE sbirthday =(SELECT MAX(SBIRTHDAY) FROM
student);

40、以班号和年龄从大到小的顺序查询Student表中的全部记录。
SELECT  class ,(YEAR(NOW())-YEAR(SBIRTHDAY)) AS age FROM student ORDER BY class DESC,age DESC
41、查询“男”教师及其所上的课程。
SELECT  c.cname FROM teacher t,course c  WHERE t.tno=c.tno AND  TSEX ='男'
SELECT A.TNAME,B.CNAME FROM TEACHER A JOIN COURSE B USING(TNO) WHERE A.TSEX='男';
42、查询最高分同学的Sno、Cno和Degree列。
SELECT st.sno,c.cno ,sc.degree FROM score sc JOIN (student st,course c) ON (sc.sno=st.sno AND sc.cno = c.cno ) WHERE sc.degree=(SELECT MAX(degree) FROM score )
SELECT MAX(degree) FROM score 

43、查询和“李军”同性别的所有同学的Sname.
SELECT ssex FROM student WHERE sname='李军'
SELECT * FROM student WHERE ssex=(SELECT ssex FROM student WHERE sname='李军')
44、查询和“李军”同性别并同班的同学Sname.
SELECT * FROM student WHERE ssex=(SELECT ssex FROM student WHERE sname='李军') AND class=(SELECT class FROM student WHERE sname='李军')
45、查询所有选修“计算机导论”课程的“男”同学的成绩表
SELECT * FROM course WHERE cname ='计算机导论'
SELECT sc.degree FROM score sc JOIN (student st,course c) ON (sc.sno=st.sno AND sc.cno = c.cno )WHERE c.cname='计算机导论' AND st.ssex='男'
SELECT A.* FROM SCORE A JOIN (STUDENT B,COURSE C) USING(sno,CNO) WHERE B.SSEX='男'
解法二：SELECT * FROM score WHERE sno IN(SELECT sno FROM student WHERE
ssex='男') AND cno=(SELECT cno FROM course
WHERE cname='计算机导论');