mysql -4练习

--创造学生情况表并添加数据
CREATE TABLE student(
     Sno VARCHAR(20) PRIMARY KEY,
     Sname VARCHAR(20) NOT NULL,
     Ssex  VARCHAR(20) NOT NULL,
     Sbirthday DATETIME,
     Class VARCHAR(20)
)
DELETE FROM student;
SELECT * FROM student;
INSERT INTO student VALUES(108,'曾华','男','1977-09-01',95033);
INSERT INTO student VALUES(105,'匡明','男','1975-10-02',95031);
INSERT INTO student VALUES(107,'王丽','女','1976-01-23',95033);
INSERT INTO student VALUES(101,'李军','男','1976-02-20',95033);
INSERT INTO student VALUES(109,'王芳','女','1975-02-10',95031);
INSERT INTO student VALUES(103,'陆君','男','1974-06-03',95031);
--创造课程表并添加数据
CREATE TABLE course(
 Cno VARCHAR(20) PRIMARY KEY,
 Cname VARCHAR(20) NOT NULL,
 Tno VARCHAR(20) NOT NULL
 )
 
 SELECT * FROM course;
 
INSERT INTO course VALUES('3-105','计算机导论',825);
INSERT INTO course VALUES('3-245','操作系统',804);
INSERT INTO course VALUES('6-166','数字电路',856);
INSERT INTO course VALUES('9-888','高等数学',831);
--创造课程表并添加数据 
 CREATE TABLE score(
   Sno VARCHAR(20) NOT NULL,
   Cno VARCHAR(20) NOT NULL,
   Degree DECIMAL(4,1) 
 )
 
DELETE FROM score ;
SELECT * FROM score;

INSERT INTO score VALUES('103','3-245',86); 
INSERT INTO score VALUES('105','3-245',75);
INSERT INTO score VALUES('109','3-245',68); 
INSERT INTO score VALUES('103','3-105',92);
INSERT INTO score VALUES('105','3-105',88);
INSERT INTO score VALUES('109','3-105',76);
INSERT INTO score VALUES('101','3-105',64);
INSERT INTO score VALUES('107','3-105',91);
INSERT INTO score VALUES('108','3-105',78);   
INSERT INTO score VALUES('101','6-166',85);  
INSERT INTO score VALUES('107','6-166',79);   
INSERT INTO score VALUES('108','6-166',81); 
 
--创造教师情况表并添加数据
 CREATE TABLE teacher(
     Tno VARCHAR(20) PRIMARY KEY,
     Tname VARCHAR(20) NOT NULL,
     Tsex VARCHAR(20) NOT NULL,
     Tbirthday DATETIME,
     Prof VARCHAR(20),
     Depart VARCHAR(20) NOT NULL
     ); 
 
 SELECT * FROM teacher;
 
 INSERT INTO teacher VALUES('804','李诚','男','1985-12-02','副教授','计算机系');
 INSERT INTO teacher VALUES('856','张旭','男','1969-03-12','讲师','电子工程系');
 INSERT INTO teacher VALUES('825','王萍','女','1972-05-05','助教','计算机系');
 INSERT INTO teacher VALUES('831','刘冰','女','1977-08-14','助教','电子工程系');
 
 
--  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 > 60 AND degree < 80;
-- 5、 查询Score表中成绩为85，86或88的记录。
SELECT * FROM score WHERE degree =85 OR degree =86 OR degree =88;
-- 6、 查询Student表中“95031”班或性别为“女”的同学记录。
--  以Class降序查询Student表的所有记录。
--  以Sno升序、Degree降序查询Score表的所有记录。
--  查询“95031”班的学生人数。
 SELECT * FROM student WHERE class = '95031' OR Ssex = '女';
 SELECT * FROM student ORDER BY class DESC;
 SELECT * FROM score ORDER BY cno ASC,degree DESC ;
 SELECT COUNT(class) FROM student WHERE class = '95031' ;
 
--  10、 查询Score表中的最高分的学生学号和课程号。（子查询或者排序）
--  查询每门课的平均成绩。
SELECT sno,cno FROM score WHERE degree =(SELECT MAX(degree) FROM score);
SELECT AVG(degree),cno FROM score GROUP BY cno;

-- 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。
-- 查询分数大于70，小于90的Sno列。
-- 查询所有学生的Sname、Cno和Degree列。
SELECT AVG(degree) FROM score GROUP BY cno HAVING cno LIKE '3%' AND COUNT(cno)>5;
SELECT sno FROM score WHERE degree>70 AND degree<90;
SELECT sname,cno,degree FROM score JOIN student ON score.`Sno` = student.`Sno` ;
-- 15、查询所有学生的Sno、Cname和Degree列。
SELECT sno,cname,degree FROM score JOIN course ON score.`Cno` = course.`Cno`;
-- 16、查询所有学生的Sname、Cname和Degree列。
SELECT sname,cname,degree FROM (student JOIN score ON student.sno =  score.`Sno`) JOIN course ON score.`Cno`=course.`Cno`;
-- 17、 查询“95033”班学生的平均分。
--  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 AVG(degree) FROM score JOIN student ON score.`Sno` = student.`Sno` WHERE class = '95033';
SELECT * FROM score JOIN student ON score.`Sno` = student.`Sno`  WHERE cno = '3-105' AND degree>(SELECT degree FROM score WHERE sno='109' AND cno='3-105' );

-- 20、查询score中选学多门课程的同学中分数为非最高分成绩的记录。
  SELECT * FROM score  WHERE degree <> ALL(SELECT MAX(degree) FROM score GROUP BY cno) AND 
  sno IN(SELECT sno FROM score GROUP BY sno HAVING COUNT(sno)>1);     
--   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 * FROM score WHERE degree>(SELECT degree FROM score WHERE sno = '109' AND cno ='3-105');      
-- 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 YEAR(sbirthday) = (SELECT YEAR(sbirthday) FROM student WHERE sno = '108');
-- 23、查询“张旭“教师任课的学生成绩（姓名）。
-- 1、从成绩表 查询学生成绩  
-- 
-- 2、条件是这个课程是 “张旭“教师任课
-- A)从老师表 中查名字叫 张旭 编号
-- B)根据老师编号 在课程表中找到对应的 课程号
SELECT sname,degree FROM student JOIN score ON student.`Sno`=score.`Sno`
WHERE cno =( SELECT cno FROM course WHERE tno = (SELECT tno FROM teacher WHERE tname = '张旭'));