上網找了個sql查詢練習題，想看看自己完成的咋樣，感覺都不難，45道題全部攻破,有些題給了2種解法，事實上很多子查詢能搞定的，連線查詢也可以。

#28題想了一會想有了答案,腦瓜子還是不夠靈動啊！

#學生表
CREATE TABLE STUDENT
(SNO VARCHAR(3) NOT NULL, 
SNAME VARCHAR(4) NOT NULL,
SSEX VARCHAR(2) NOT NULL, 
SBIRTHDAY DATETIME,
CLASS VARCHAR(5))ENGINE=MyISAM AUTO_INCREMENT=348 DEFAULT CHARSET=utf8 ;
 


#課程表
CREATE TABLE COURSE
(CNO VARCHAR(5) NOT NULL, 
CNAME VARCHAR(10) NOT NULL, 
TNO VARCHAR(10) NOT NULL)ENGINE=MyISAM AUTO_INCREMENT=348 DEFAULT CHARSET=utf8 ;

#成績表
CREATE TABLE SCORE 
(SNO VARCHAR(3) NOT NULL, 
CNO VARCHAR(5) NOT NULL, 
DEGREE NUMERIC(10, 1) NOT NULL)ENGINE=MyISAM AUTO_INCREMENT=348
 
 DEFAULT CHARSET=utf8 ;

#教師表
CREATE TABLE TEACHER 
(TNO VARCHAR(3) NOT NULL, 
TNAME VARCHAR(4) NOT NULL, TSEX VARCHAR(2) NOT NULL, 
TBIRTHDAY DATETIME NOT NULL,
PROF VARCHAR(6), 
DEPART VARCHAR(10) NOT NULL)ENGINE=MyISAM AUTO_INCREMENT=348 DEFAULT CHARSET=utf8 ;




INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES
 
 (108 ,'曾華' 
,'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 ,'王麗' 
,'女' ,'1976-01-23',95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (101 ,'李軍' 
,'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 ,'陸君' 
,'男' ,'1974-06-03',95031);


INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-105' ,'計算機導論',825);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-245' ,'作業系統' ,804);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('6-166' ,'資料電路' ,856);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('9-888' ,'高等數學' ,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,'李誠','男','1958-12-02','副教授','計算機系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART) 
VALUES (856,'張旭','男','1969-03-12','講師','電子工程系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (825,'王萍','女','1972-05-05','助教','計算機系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART) 
VALUES (831,'劉冰','女','1977-08-14','助教','電子工程系');

#####################################################
         #我是華麗麗的分割線
#####################################################

#1、 查詢Student表中的所有記錄的Sname、Ssex和Class列。
SELECT sname,ssex,class from student;

#2、 查詢教師所有的單位即不重複的Depart列。
SELECT DISTINCT depart from teacher;

#3、 查詢Student表的所有記錄。
SELECT * from student;

#4、 查詢Score表中成績在60到80之間的所有記錄。
SELECT * from score WHERE degree BETWEEN 60 and 80;
SELECT * from score WHERE degree >= 60 and degree <=80;

#5、 查詢Score表中成績為85，86或88的記錄。
SELECT * from score WHERE degree in(85,86,88);
SELECT * from score WHERE degree = 85 or degree = 86 or degree = 88;

#6、 查詢Student表中“95031”班或性別為“女”的同學記錄。
SELECT * from student WHERE class= '95031' or ssex = '女';

#7、 以Class降序查詢Student表的所有記錄。
SELECT * from student ORDER BY class desc;

#8、 以Cno升序、Degree降序查詢Score表的所有記錄。
SELECT * from score ORDER BY cno asc, degree DESC;

#9、 查詢“95031”班的學生人數。
SELECT COUNT(class) as  95031班的學生人數 from student WHERE class = '95031';

#10、查詢Score表中的最高分的學生學號和課程號。
SELECT sno,cno from score WHERE degree = (SELECT MAX(degree) from score);

#11、查詢‘3-105’號課程的平均分。
SELECT avg(degree) 平均分  from score GROUP BY cno HAVING cno = '3-105';

#12、查詢Score表中至少有5名學生選修的並以3開頭的課程的平均分數。
SELECT cno ,avg(degree) 平均分 from score GROUP BY cno HAVING COUNT(*) >=5 and cno like '3%';

#13、查詢最低分大於70，最高分小於90的Sno列。
SELECT sno from score GROUP BY sno HAVING MIN(degree)>70 and MAX(degree) < 90;

#14、查詢所有學生的Sname、Cno和Degree列。
SELECT  sname,cno,degree  from student as stu INNER JOIN score as s on stu.sno = s.sno;

#15、查詢所有學生的Sno、Cname和Degree列。
SELECT s.sno,cname,degree from  student stu INNER JOIN score s INNER JOIN course c on stu.sno = s.sno and c.cno = s.cno;

#16、查詢所有學生的Sname、Cname和Degree列。
SELECT sname,cname,degree from  student stu INNER JOIN score s INNER JOIN course c on stu.sno = s.sno and c.cno = s.cno;

#17、查詢“95033”班所選課程的平均分。
#子查詢實現
SELECT cno , avg(degree) 平均分  from score  WHERE sno in (SELECT sno from student WHERE class = '95033') GROUP BY cno;
#連線查詢實現
SELECT cno , avg(degree) 平均分  from student stu INNER JOIN score s  on stu.sno = s.sno and class = '95033' GROUP BY cno;

#18、假設使用如下命令建立了一個grade表：
create table grade(low decimal(3,0),upp decimal(3,0),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');

#現查詢所有同學的Sno、Cno和rank列。
SELECT s.sno,c.cno,degree,rank from  student stu INNER JOIN score s INNER JOIN course c INNER JOIN grade on stu.sno = s.sno and c.cno = s.cno and degree>= grade.low and degree<=grade.upp;

#19、查詢選修“3-105”課程的成績高於“109”號同學成績的所有同學的記錄。
SELECT * from student WHERE sno in (SELECT sno  from score WHERE degree > (SELECT degree from score WHERE sno='109' and cno='3-105') and cno='3-105');
SELECT stu.*  from student as stu INNER JOIN score as s on stu.sno = s.sno and cno='3-105' and degree > (SELECT degree from score WHERE sno='109' and cno='3-105') ;

#20、查詢score中選學一門以上課程的同學中分數為非最高分成績的記錄。
SELECT score.* from score INNER JOIN (SELECT sno ,MAX(degree) as maxdegree from score GROUP BY sno HAVING COUNT(*) >1) temp on score.sno = temp.sno and score.degree < temp.maxdegree;

#21、查詢成績高於學號為“109”、課程號為“3-105”的成績的所有記錄。
SELECT s.*  from student as stu INNER JOIN score as s on stu.sno = s.sno and cno='3-105' and degree > (SELECT degree from score WHERE sno='109' and cno='3-105') ;

#22、查詢和學號為107的同學同年出生的所有學生的Sno、Sname和Sbirthday列。
SELECT sno ,sname,sbirthday from student WHERE year(sbirthday) = (SELECT year(sbirthday) from student WHERE sno='107');

#23、查詢“張旭“教師任課的學生成績。
SELECT * from score WHERE cno in (SELECT cno from course WHERE tno = (SELECT tno from teacher WHERE tname ='張旭'));

#24、查詢選修某課程的同學人數多於5人的教師姓名。
SELECT tname from teacher WHERE tno in (SELECT tno from course WHERE cno in (SELECT cno from score GROUP BY cno HAVING COUNT(*)>5));

#25、查詢95033班和95031班全體學生的記錄。
SELECT * from student WHERE CLASS = '95033' or CLASS = '95031';

#26、查詢存在有85分以上成績的課程Cno.
SELECT cno from score GROUP BY cno HAVING MAX(degree) >= 85;

#27、查詢出“計算機系“教師所教課程的成績表。
SELECT * from score WHERE cno in (SELECT CNO from course WHERE TNO in (SELECT tno from teacher WHERE DEPART = '計算機系'));

#28、查詢“計算機系”與“電子工程系“不同職稱的教師的Tname和Prof。
SELECT tname ,prof from teacher WHERE DEPART = '計算機系' and  prof not in (SELECT prof from teacher WHERE DEPART = '電子工程系')
UNION
SELECT tname ,prof from teacher WHERE DEPART = '電子工程系' and  prof not in (SELECT prof from teacher WHERE DEPART = '計算機系');

#29、查詢選修編號為“3-105“課程且成績至少高於選修編號為“3-245”的同學的Cno、Sno和Degree,並按Degree從高到低次序排序。
SELECT sno, cno ,degree from score WHERE CNO = '3-105' and DEGREE > ANY(SELECT DEGREE from score WHERE CNO = '3-245') ORDER BY degree desc;
SELECT sno, cno ,degree from score WHERE CNO = '3-105' and DEGREE > (SELECT MIN(DEGREE) from score WHERE CNO = '3-245') ORDER BY degree desc;

#30、查詢選修編號為“3-105”且成績高於選修編號為“3-245”課程的同學的Cno、Sno和Degree.
SELECT sno, cno ,degree from score WHERE CNO = '3-105' and DEGREE > ALL(SELECT DEGREE from score WHERE CNO = '3-245') ORDER BY degree desc;
SELECT sno, cno ,degree from score WHERE CNO = '3-105' and DEGREE > (SELECT MAX(DEGREE) from score WHERE CNO = '3-245') ORDER BY degree desc;

#31、查詢所有教師和同學的name、sex和birthday.
SELECT sname as name , ssex as sex , sbirthday as birthday from student
UNION ALL #萬一老師和學生姓名 性別 出生日相同呢 所以加了ALL
SELECT tname , tsex  , tbirthday as birthday from teacher;

#32、查詢所有“女”教師和“女”同學的name、sex和birthday.
SELECT sname as name , ssex as sex , sbirthday as birthday from student WHERE ssex = '女'
UNION ALL 
SELECT tname , tsex  , tbirthday as birthday from teacher WHERE tsex = '女';

#33、查詢成績比該課程平均成績低的同學的成績表。
SELECT sno, cno as score_cno ,degree  from score WHERE DEGREE < (SELECT avg(DEGREE) FROM score GROUP BY CNO HAVING  CNO = score_cno );

SELECT A.* from score as A  INNER JOIN (SELECT cno , avg(DEGREE)  as avgdegree FROM score GROUP BY CNO) as B  on A.cno = B.cno and A.DEGREE < B.avgdegree;

#34、查詢所有任課教師的Tname和Depart.
SELECT tname,depart from teacher WHERE TNO in (SELECT tno from course);

#35、查詢所有未講課的教師的Tname和Depart. 
SELECT tname,depart from teacher WHERE TNO not in (SELECT tno from course);

#36、查詢至少有2名男生的班號。
SELECT class from  student GROUP BY class HAVING COUNT(class)>1;

#37、查詢Student表中不姓“王”的同學記錄。
SELECT * from student WHERE sname not like '王%';

#38、查詢Student表中每個學生的姓名和年齡。
SELECT sname ,TIMESTAMPDIFF(YEAR,sbirthday,NOW()) as age from student;

#39、查詢Student表中最大和最小的Sbirthday日期;。
SELECT  MAX(sbirthday),MIN(sbirthday) from student ;

#40、以班號和年齡從大到小的順序查詢Student表中的全部記錄。
SELECT * from student ORDER BY class desc,sbirthday desc;

#41、查詢“男”教師及其所上的課程。
SELECT * from course WHERE TNO in (SELECT TNO from teacher WHERE TSEX = '男');

#42、查詢最高分同學的Sno、Cno和Degree列。
SELECT stu.sno,s.cno,s.degree from student stu INNER JOIN score s on stu.sno=s.sno and s.degree = (select max(degree) from score);

#43、查詢和“李軍”同性別的所有同學的Sname.
SELECT sname from student WHERE ssex  = (SELECT ssex from student where sname='李軍');

#44、查詢和“李軍”同性別並同班的同學Sname.
SELECT sname from student WHERE ssex  = (SELECT ssex from student where sname='李軍') and class = (SELECT class from student where sname='李軍');

#45、查詢所有選修“計算機導論”課程的“男”同學的成績表
SELECT score.* from student INNER JOIN score INNER JOIN course on student.SNO = score.SNO AND score.CNO = course.CNO AND course.CNAME = '計算機導論' AND student.SSEX = '男';