Python/ MySQL练习题(一)

2、查询“生物”课程比“物理”课程成绩高的所有学生的学号

1 SELECT2 *

3 FROM4 (5 SELECT6 *

7 FROM8 course9 LEFT JOIN score ON score.course_id =course.cid10 WHERE11 course.cname = ‘生物‘

12 ) AS A13 INNER JOIN (14 SELECT15 *

16 FROM17 course18 LEFT JOIN score ON score.course_id =course.cid19 WHERE20 course.cname = ‘物理‘

21 ) AS B ON A.student_id =B.student_id22 WHERE23 A.num > B.num

3、查询平均成绩大于60分的同学的学号和平均成绩

1 SELECT2 B.student_id,3 student.sname,4 B.cc5 FROM6 (7 SELECT8 student_id,9 num,10 avg(num) AS cc11 FROM12 score13 GROUP BY14 student_id15 HAVING16 avg(num) > 60

17 ) AS B18 LEFT JOIN student ON B.student_id = student.sid

4、查询所有同学的学号、姓名、选课数、总成绩

1 SELECT2 student_id,3 student.sname,4 count(score.course_id)as cc,5 sum(num)as cj6 FROM7 student8 LEFT JOIN score ON score.student_id =student.sid9 GROUP BY10 score.student_id

5、查询姓“李”的老师的个数

1 SELECT * from teacher where tname like ‘李%‘

6、查询没学过“李平”老师课的同学的学号、姓名

1 SELECT student.sid,student.sname from student where sid not in

2 (SELECT3 student_id4 FROM5 score6 WHERE course_id IN7 (8 SELECT9 course.cid10 FROM11 course12 LEFT JOIN teacher ON teacher.tid =course.teacher_id13 WHERE14 tname = ‘李平老师‘

15 ) GROUP BY student_id)

7、查询学过“001”并且也学过编号“002”课程的同学的学号、姓名

1 select A.student_id,B.sname FROM (SELECT score.student_id,student.sname,course_id2 from score LEFT JOIN student on student.sid=score.student_id where score.course_id=‘1‘)as A3 LEFT JOIN(SELECT score.student_id,student.sname,course_id4 from score LEFT JOIN student on student.sid=score.student_id where score.course_id=‘2‘)as B5 on A.student_id=B.student_id6 where A.course_id=1 and B.course_id=2;

8、查询学过“李平”老师所教的所有课的同学的学号、姓名

1 SELECT2 student.sid,3 student.sname4 FROM5 student6 WHERE7 student.sid NOT IN (8 SELECT9 student.sname10 FROM11 student12 WHERE13 student.sid IN (14 SELECT15 course.cid16 FROM17 course18 LEFT JOIN teacher ON teacher.tid =course.teacher_id19 WHERE20 teacher.tname = ‘李平老师‘

21 )22 )

9、查询课程编号“002”的成绩比课程编号“001”课程低的所有同学的学号、姓名

1 SELECT2 student.sid,3 student.sname4 FROM5 (6 SELECT7 *

8 FROM9 score10 WHERE11 score.course_id = ‘2‘

12 ) AS A13 LEFT JOIN (14 SELECT15 *

16 FROM17 score18 WHERE19 score.course_id = ‘1‘

20 ) AS B ON A.student_id =B.student_id21 LEFT JOIN student ON student.sid =B.student_id22 WHERE23 A.num < B.num

10、查询有课程成绩小于60分的同学的学号、姓名

1 SELECT2 student.sid,3 student.sname4 FROM5 score6 LEFT JOIN course ON course.cid =score.course_id7 LEFT JOIN student ON student.sid =score.student_id8 WHERE9 score.num < 60

10 GROUP BY11 student_id

11、查询没有学全所有课的同学的学号、姓名

1 SELECT2 student.sid,3 student.sname4 FROM5 student6 WHERE7 student.sid NOT IN (8 SELECT9 student.sid10 FROM11 score12 LEFT JOIN course ON course.cid =score.course_id13 LEFT JOIN student ON student.sid =score.student_id14 GROUP BY15 score.student_id16 HAVING17 count(course_id) =(SELECT COUNT(cid) FROM course)18 )

12、查询至少有一门课与学号为“001”的同学所学相同的同学的学号和姓名

1 SELECT2 *

3 FROM4 score5 LEFT JOIN student on score.student_id =student.sid6 LEFT JOIN course ON course.cid =score.course_id7 WHERE student_id != 1AND8 score.course_id in(9 SELECT10 course_id11 FROM12 score13 WHERE14 student_id = 1

15 )16 GROUP BY student_id

13、查询至少学过学号为“001”同学所选课程中任意一门课的其他同学学号和姓名

1 SELECT student_id from score where student_id!=1 andcourse_id IN2 (select course_id from score where student_id =1GROUP BY course_id)3 GROUP BY student_id

14、查询和“002”号的同学学习的课程完全相同的其他同学学号和姓名

1 SELECT2 student_id,3 sname4 FROM5 score6 LEFT JOIN student ON score.student_id =student.sid7 WHERE8 student_id IN (9 SELECT10 student_id11 FROM12 score13 WHERE14 student_id != 1

15 GROUP BY16 student_id17 HAVING18 count(course_id) =(19 SELECT20 count(1)21 FROM22 score23 WHERE24 student_id = 1

25 )26 )27 AND course_id IN (28 SELECT29 course_id30 FROM31 score32 WHERE33 student_id = 1

34 )35 GROUP BY36 student_id37 HAVING38 count(course_id) =(39 SELECT40 count(1)41 FROM42 score43 WHERE44 student_id = 1

45 )

15、删除学习“李平”老师课的SC表记录

1 DELETE FROM score where score.course_id IN2 (SELECT course_id from course LEFT JOIN teacher on teacher.tid=course.teacher_id3 LEFT JOIN score on score.course_id=course.cid4 LEFT JOIN student on score.student_id=student.sid5 WHERE teacher.tname=‘李平老师‘

6 GROUP BY course_id;)

16、向SC表中插入一些记录，这些记录要求符合以下条件：①没有上过编号“002”课程的同学学号；②插入“002”号课程的平均成绩

1 insert into score (student_id,course_id,num)SELECT student_id,1,FLOOR(avg(num))2 (SELECT student_id from score where course_id !=2

3 SELECT FLOOR(avg(num))from score where course_id = 2)

17、按平均成绩从低到高显示所有学生的“语文”、“数学”、“英语”三门的课程成绩，按如下形式显示： 学生ID,语文,数学,英语,有效课程数,有效平均分

1 select sc.student_id,2 (select num from score left join course on score.course_id = course.cid where course.cname = "生物" and score.student_id=sc.student_id) as sy,3 (select num from score left join course on score.course_id = course.cid where course.cname = "物理" and score.student_id=sc.student_id) as wl,4 (select num from score left join course on score.course_id = course.cid where course.cname = "体育" and score.student_id=sc.student_id) as ty,5 count(sc.course_id),6 avg(sc.num)7 fromscore as sc8 group by student_id desc

18、查询各科成绩最高和最低的分：以如下形式显示：课程ID，最高分，最低分

1 select student_id,MAX(num),MIN(num) from score GROUP BY course_id

19、按各科平均成绩从低到高和及格率的百分数从高到低顺序

1 SELECT2 course_id,3 avg(num) AS nn,4 sum(5 CASE6 WHEN num < 60THEN7 08 ELSE9 1

10 END11 ),12 SUM(1),13 sum(14 CASE15 WHEN num < 60THEN16 017 ELSE18 1

19 END20 ) / SUM(1) AS pj21 FROM22 score23 GROUP BY24 course_id25 ORDER BY26 avg(num) DESC

20、课程平均分从高到低显示(现实任课老师)

1 SELECT score.course_id,course.cname,avg(num),teacher.tname from score LEFT JOIN course on course.cid=score.course_id2 LEFT JOIN teacher on teacher.tid=course.teacher_id3 GROUP BY course_id4

5 HAVING avg(num)6 ORDER BY avg(num) DESC