MySQL 45道练习题

student

course

score

teacher

-- 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;
SELECT * FROM score WHERE degree BETWEEN 60 AND 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。
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 class,COUNT(*) FROM student GROUP BY class HAVING 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）
SELECT sno,cno FROM score WHERE degree=(SELECT MAX(degree) FROM score);
SELECT sno,cno FROM score ORDER BY degree DESC LIMIT 0,1;
-- 11、查询每门课的平均成绩。
SELECT cno,AVG(degree) 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。
SELECT AVG(degree) AS '平均数' FROM score WHERE cno LIKE '3%' GROUP BY cno HAVING COUNT(*)>5;
-- 13、查询分数大于70，小于90的Sno列。
SELECT sno FROM score WHERE degree BETWEEN 70 AND 90;
-- 14、查询所有学生的Sname、Cno和Degree列
SELECT sname,cno,degree FROM student JOIN score ON student.sno=score.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
SELECT class,AVG(degree) FROM student JOIN score ON student.sno=score.sno GROUP BY class HAVING class='95033';
-- 18、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 * FROM student JOIN score ON student.sno=score.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
-- 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 student JOIN score ON student.sno=score.sno
 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）。
SELECT sname,degree FROM teacher JOIN course ON teacher.tno=course.tno JOIN score ON course.cno=score.cno JOIN student ON score.sno=student.sno
 WHERE tname='张旭';
-- 24、查询考计算机导论的学生成绩
SELECT sname,degree FROM teacher JOIN course ON teacher.tno=course.tno JOIN score ON course.cno=score.cno JOIN student ON score.sno=student.sno
 WHERE cname='计算机导论';
-- 25、查询李诚老师教的课程名称
SELECT DISTINCT cname FROM teacher JOIN course ON teacher.tno=course.tno JOIN score ON course.cno=score.cno JOIN student ON score.sno=student.sno
 WHERE tname='李诚';
-- 26、教高等数学的老师是哪个系的
SELECT depart FROM teacher RIGHT JOIN course ON teacher.tno=course.tno LEFT JOIN score ON course.cno=score.cno LEFT JOIN student ON score.sno=student.sno
 WHERE cname='高等数学';
-- 27、查询选修某课程的同学人数多于5人的教师姓名。
SELECT DISTINCT tname FROM teacher RIGHT JOIN course ON teacher.tno=course.tno LEFT JOIN score ON course.cno=score.cno LEFT JOIN student ON score.sno=student.sno
 WHERE  course.cno=(SELECT cno FROM score GROUP BY cno HAVING COUNT(*)>5);
-- 28、查询95033班和95031班全体学生的记录。
SELECT * FROM teacher RIGHT JOIN course ON teacher.tno=course.tno LEFT JOIN score ON course.cno=score.cno LEFT JOIN student ON score.sno=student.sno
 WHERE class='95031' OR class='95033';
 -- 29、 查询存在有85分以上成绩的课程Cno
SELECT DISTINCT score.cno FROM teacher RIGHT JOIN course ON teacher.tno=course.tno LEFT JOIN score ON course.cno=score.cno LEFT JOIN student ON score.sno=student.sno
 WHERE  degree>85;
 -- 30、查询出“计算机系“教师所教课程的成绩表。
 SELECT degree FROM score WHERE cno IN (SELECT cno FROM teacher JOIN course ON teacher.tno=course.tno WHERE depart='计算机系');
 -- 31、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,并按Degree从高到低次序排序。
SELECT sno,cno,degree FROM score WHERE degree>ALL(SELECT degree FROM score WHERE cno='3-245') AND cno='3-105' ORDER BY degree DESC;
 -- 32、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.
SELECT sno,cno,degree FROM score WHERE degree>ANY(SELECT degree FROM score WHERE cno='3-245') AND cno='3-105' ;
-- 33、查询所有教师和同学的name、sex和birthday
SELECT tname AS 'name',tsex AS 'sex',tbirthday AS 'birthday' FROM teacher
UNION
SELECT sname AS 'name',ssex AS 'sex',sbirthday AS 'birthday' FROM student;
-- 34、查询所有“女”教师和“女”同学的name、sex和birthday
SELECT tname AS 'name',tsex AS 'sex',tbirthday AS 'birthday' FROM teacher WHERE tsex='女'
UNION
SELECT sname AS 'name',ssex AS 'sex',sbirthday AS 'birthday' FROM student WHERE ssex='女';
-- 35、查询成绩比该课程平均成绩低的同学的成绩表。
SELECT * FROM score a WHERE degree<(SELECT AVG(degree) FROM score b WHERE a.cno=b.cno);
-- 36、 查询所有任课教师的Tname和Depart.
SELECT tname,depart FROM teacher;
-- 37、查询所有未讲课的教师的Tname和Depart

-- 38、查询至少有2名男生的班号。
SELECT class FROM student WHERE ssex='男' GROUP BY class HAVING COUNT(*)>1;
-- 39、查询Student表中不姓“王”的同学记录。
SELECT * FROM student WHERE sname NOT LIKE'王%';
-- 40、查询Student表中每个学生的姓名和年龄。
SELECT sname,YEAR(NOW())-YEAR(sbirthday) FROM student;
-- 41、查询Student表中最大和最小的Sbirthday日期值。
SELECT MAX(sbirthday),MIN(sbirthday) FROM student;
-- 42、以班号和年龄从大到小的顺序查询Student表中的全部记录。
SELECT * FROM student ORDER BY class DESC,sbirthday ASC;
-- 43、查询“男”教师及其所上的课程。
SELECT tname,cname FROM teacher JOIN course ON teacher.tno=course.tno WHERE tsex='男';
-- 44、查询最高分同学的Sno、Cno和Degree列。
SELECT sno,cno,degree FROM  score WHERE degree=(SELECT MAX(degree) FROM score);
-- 45、查询和“李军”同性别的所有同学的Sname.
SELECT sname FROM student WHERE ssex=(SELECT ssex FROM student WHERE sname='李军') 
AND sname <> ('李军');
-- 46、查询和“李军”同性别并同班的同学Sname.
SELECT sname FROM student WHERE ssex=(SELECT ssex FROM student WHERE sname='李军') 
AND class=(SELECT class FROM student WHERE sname='李军') 
AND sname <> ('李军');
-- 47、查询所有选修“计算机导论”课程的“男”同学的成绩表。
SELECT sname,degree FROM student
JOIN score ON student.sno=score.sno
JOIN course ON score.cno=course.cno WHERE cname='计算机导论' AND ssex='男';