Mysql练习45题
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- 1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数
- 2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数SELECT
- 3、查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩
- 4、查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩
- 5、查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩
- 6、查询"李"姓老师的数量
- 7、查询学过"张三"老师授课的同学的信息
- 8、查询没学过"张三"老师授课的同学的信息
- 9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息
- 10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息
- 11、查询没有学全所有课程的同学的信息
- 12、查询至少有一门课与学号为"01"的同学所学相同的同学的信息
- 13、查询和"01"号的同学学习的课程完全相同的其他同学的信息
- 14、查询没学过"张三"老师讲授的任一门课程的学生姓名
- 15、查询两门及其以上不及格课程的同学的学号,姓名及其平均成绩
- 16、检索"01"课程分数小于60,按分数降序排列的学生信息
- 17、按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩
- 18.查询各科成绩最高分、最低分和平均分:以如下形式显示:课程ID,课程name,最高分,最低分,平均分,及格率,中等率,优良率,优秀率
- 19、按各科成绩进行排序,并显示排名(实现不完全)
- 20、查询学生的总成绩并进行排名
- 21、查询不同老师所教不同课程平均分从高到低显示
- 22、查询所有课程的成绩第2名到第3名的学生信息及该课程成绩
- 23、统计各科成绩各分数段人数:课程编号,课程名称,[100-85],[85-70],[70-60],[0-60]及所占百分比
- 24、查询学生平均成绩及其名次
- 25、查询各科成绩前三名的记录
- 26、查询每门课程被选修的学生数
- 27、查询出只有两门课程的全部学生的学号和姓名
- 28、查询男生、女生人数
- 29、查询名字中含有"风"字的学生信息
- 30、查询同名同性学生名单,并统计同名人数
- 31、查询1990年出生的学生名单
- 32、查询每门课程的平均成绩,结果按平均成绩降序排列,平均成绩相同时,按课程编号升序排列
- 33、查询平均成绩大于等于85的所有学生的学号、姓名和平均成绩
- 34、查询课程名称为"数学",且分数低于60的学生姓名和分数
- 35、查询所有学生的课程及分数情况;
- 36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数
- 37、查询不及格的课程
- 38、查询课程编号为01且课程成绩在80分以上的学生的学号和姓名
- 39、求每门课程的学生人数
- 40、查询选修"张三"老师所授课程的学生中,成绩最高的学生信息及其成绩
- 41、查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩
- 42、查询每门功成绩最好的前两名
- 44、检索至少选修两门课程的学生学号
- 45、查询选修了全部课程的学生信息
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1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数
SELECT st.*,sc.s_score AS '语文' ,sc2.s_score AS '数学'
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id AND sc.c_id='01'
LEFT JOIN score sc2 ON sc2.s_id=st.s_id AND sc2.c_id='02'
WHERE sc.s_score>sc2.s_score
2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数SELECT
st.*,sc.s_score AS '语文' ,sc2.s_score '数学'
SELECT st.*,sc.s_score AS '语文' ,sc2.s_score AS '数学'
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id AND sc.c_id='01'
LEFT JOIN score sc2 ON sc2.s_id=st.s_id AND sc2.c_id='02'
WHERE sc.s_score<sc2.s_score
3、查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩
SELECT st.s_id,st.s_name,AVG(sc.s_score) AS '平均成绩'
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id HAVING AVG(sc.s_score)>=60
4、查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩
-- (包括有成绩的和无成绩的)
SELECT st.s_id,st.s_name,IFNULL(AVG(sc.s_score),0) AS '平均成绩'
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id HAVING AVG(sc.s_score)<60 OR AVG(sc.s_score) IS NULL
5、查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩
SELECT st.s_id,st.s_name,COUNT(c.c_id) AS '选课总数',IFNULL(SUM(sc.s_score),0) AS '总成绩'
FROM student st
LEFT JOIN score sc ON sc.s_id =st.s_id
LEFT JOIN course c ON c.c_id=sc.c_id
GROUP BY st.s_id
6、查询"李"姓老师的数量
SELECT t.t_name,COUNT(t.t_id) AS '数量' FROM teacher t
GROUP BY t.t_id HAVING t.t_name LIKE "李%";
7、查询学过"张三"老师授课的同学的信息
SELECT st.*
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
LEFT JOIN course c ON c.c_id=sc.c_id
LEFT JOIN teacher t ON t.t_id=c.t_id
WHERE t.t_name="张三"
8、查询没学过"张三"老师授课的同学的信息
SELECT st.*
FROM student st
WHERE st.s_id NOT IN(
SELECT sc.s_id FROM score sc
LEFT JOIN course c ON c.c_id=sc.c_id
LEFT JOIN teacher t ON t.t_id=c.t_id
WHERE t.t_name="张三"
)
9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息
SELECT st.*
FROM student st
INNER JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id
HAVING SUM(IF(sc.c_id="01" OR sc.c_id="02" ,1,0))>1
10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息
SELECT st.*
FROM student st
INNER JOIN score sc ON sc.s_id = st.s_id
INNER JOIN course c ON c.c_id=sc.c_id AND c.c_id="01"
WHERE st.s_id NOT IN (
SELECT st2.s_id FROM student st2
INNER JOIN score sc2 ON sc2.s_id = st2.s_id
INNER JOIN course c2 ON c2.c_id=sc2.c_id AND c2.c_id="02"
)
11、查询没有学全所有课程的同学的信息
SELECT st.* FROM Student st
LEFT JOIN score sc ON st.s_id = sc.s_id
GROUP BY st.s_id HAVING COUNT(c_id)<(SELECT COUNT(c_id) FROM Course)
12、查询至少有一门课与学号为"01"的同学所学相同的同学的信息
SELECT DISTINCT st.*
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
WHERE sc.c_id IN (
SELECT sc2.c_id FROM student st2
LEFT JOIN score sc2 ON sc2.s_id=st2.s_id
WHERE st2.s_id ='01'
)
13、查询和"01"号的同学学习的课程完全相同的其他同学的信息
SELECT st.*
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id HAVING GROUP_CONCAT(sc.c_id) =
(
SELECT GROUP_CONCAT(sc2.c_id) FROM student st2
LEFT JOIN score sc2 ON sc2.s_id=st2.s_id
WHERE st2.s_id ='01'
)
14、查询没学过"张三"老师讲授的任一门课程的学生姓名
SELECT st.s_name
FROM student st
WHERE st.s_id NOT IN(
SELECT sc.s_id FROM score sc
LEFT JOIN course c ON c.c_id=sc.c_id
LEFT JOIN teacher t ON t.t_id=c.t_id
WHERE t.t_name="张三"
)
15、查询两门及其以上不及格课程的同学的学号,姓名及其平均成绩
SELECT st.s_id,st.s_name,AVG(sc.s_score)
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
WHERE sc.s_id IN (
SELECT sc.s_id FROM score sc
WHERE sc.s_score<60 OR sc.s_score IS NULL
GROUP BY sc.s_id HAVING COUNT(sc.s_id)>=2
)
GROUP BY st.s_id
16、检索"01"课程分数小于60,按分数降序排列的学生信息
SELECT st.*,sc.s_score
FROM student st
INNER JOIN score sc ON sc.s_id=st.s_id AND sc.c_id="01" AND sc.s_score<60
ORDER BY sc.s_score DESC
17、按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩
SELECT st.s_id,st.s_name,IFNULL(AVG(sc4.s_score),0) AS "平均分",IFNULL(sc.s_score,0) AS "语文",IFNULL(sc2.s_score,0) AS "数学",IFNULL(sc3.s_score,0) AS "英语"
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id AND sc.c_id="01"
LEFT JOIN score sc2 ON sc2.s_id=st.s_id AND sc2.c_id="02"
LEFT JOIN score sc3 ON sc3.s_id=st.s_id AND sc3.c_id="03"
LEFT JOIN score sc4 ON sc4.s_id=st.s_id
GROUP BY st.s_id
ORDER BY SUM(sc4.s_score) DESC
18.查询各科成绩最高分、最低分和平均分:以如下形式显示:课程ID,课程name,最高分,最低分,平均分,及格率,中等率,优良率,优秀率
------ 及格为>=60,中等为:70-80,优良为:80-90,优秀为:>=90
SELECT sc.c_id,co.c_name,MAX(sc.s_score)"最高分",MIN( sc.s_score)"最低分",AVG(sc.s_score)"平均分",
(SUM(IF(sc.s_score>=60,1,0))/COUNT(1))"及格率",(SUM(IF(sc.s_score>=70 AND sc.s_score<80,1,0))/COUNT(1))"中等率",
(SUM(IF(sc.s_score>=80 AND sc.s_score<90,1,0))/COUNT(1))"优良率",(SUM(IF(sc.s_score>=90,1,0))/COUNT(1))"优秀率"
FROM score sc
INNER JOIN course co ON co.c_id = sc.c_id
GROUP BY sc.c_id
19、按各科成绩进行排序,并显示排名(实现不完全)
SELECT s_id,a.c_id,c_name,s_score,rank FROM (
SELECT s_id,c_id,s_score,
CASE
WHEN c_id = @cid THEN
IF(@prevRank = s_score,@curRank,@curRank := @curRank + 1)
ELSE
@curRank := 1
END AS rank,
@cid := c_id,
@prevRank := s_score
FROM score, (SELECT @cid:=NULL,@prevRank:=NULL,@curRank:=0) p
ORDER BY c_id,s_score DESC) a LEFT JOIN course ON a.c_id=course.c_id
20、查询学生的总成绩并进行排名
SELECT st.s_id,st.s_name,(CASE WHEN SUM(sc.s_score) IS NULL THEN 0 ELSE SUM(sc.s_score) END)
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id ORDER BY SUM(sc.s_score) DESC
21、查询不同老师所教不同课程平均分从高到低显示
SELECT t.t_id,t.t_name,c.c_name,AVG(sc.s_score) FROM teacher t
LEFT JOIN course c ON c.t_id=t.t_id
LEFT JOIN score sc ON sc.c_id =c.c_id
GROUP BY t.t_id
ORDER BY AVG(sc.s_score) DESC
22、查询所有课程的成绩第2名到第3名的学生信息及该课程成绩
SELECT a.* FROM (
SELECT st.*,c.c_id,c.c_name,sc.s_score FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id =sc.c_id AND c.c_id="01"
ORDER BY sc.s_score DESC LIMIT 1,2 ) a
UNION ALL
SELECT b.* FROM (
SELECT st.*,c.c_id,c.c_name,sc.s_score FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id =sc.c_id AND c.c_id="02"
ORDER BY sc.s_score DESC LIMIT 1,2) b
UNION ALL
SELECT c.* FROM (
SELECT st.*,c.c_id,c.c_name,sc.s_score FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id =sc.c_id AND c.c_id="03"
ORDER BY sc.s_score DESC LIMIT 1,2) c
23、统计各科成绩各分数段人数:课程编号,课程名称,[100-85],[85-70],[70-60],[0-60]及所占百分比
SELECT c.c_id,c.c_name
,((SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id AND sc.s_score<=100 AND sc.s_score>80)/(SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id )) "100-85"
,((SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id AND sc.s_score<=85 AND sc.s_score>70)/(SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id )) "85-70"
,((SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id AND sc.s_score<=70 AND sc.s_score>60)/(SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id )) "70-60"
,((SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id AND sc.s_score<=60 AND sc.s_score>=0)/(SELECT COUNT(1) FROM score sc WHERE sc.c_id=c.c_id )) "60-0"
FROM course c ORDER BY c.c_id
24、查询学生平均成绩及其名次
SET @i=0;
SELECT a.*,@i:=@i+1 FROM (
SELECT st.s_id,st.s_name,ROUND((CASE WHEN AVG(sc.s_score) IS NULL THEN 0 ELSE AVG(sc.s_score) END),2) "平均分" FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id ORDER BY sc.s_score DESC) a
25、查询各科成绩前三名的记录
SELECT a.* FROM (
SELECT st.s_id,st.s_name,c.c_id,c.c_name,sc.s_score FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id=sc.c_id AND c.c_id='01'
ORDER BY sc.s_score DESC LIMIT 0,3) a
UNION ALL
SELECT b.* FROM (
SELECT st.s_id,st.s_name,c.c_id,c.c_name,sc.s_score FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id=sc.c_id AND c.c_id='02'
ORDER BY sc.s_score DESC LIMIT 0,3) b
UNION ALL
SELECT c.* FROM (
SELECT st.s_id,st.s_name,c.c_id,c.c_name,sc.s_score FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id=sc.c_id AND c.c_id='03'
ORDER BY sc.s_score DESC LIMIT 0,3) c
26、查询每门课程被选修的学生数
SELECT c.c_id,c.c_name,COUNT(1)
FROM course c
LEFT JOIN score sc ON sc.c_id=c.c_id
INNER JOIN student st ON st.s_id=c.c_id
GROUP BY st.s_id
27、查询出只有两门课程的全部学生的学号和姓名
SELECT st.s_id,st.s_name
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id=sc.c_id
GROUP BY st.s_id HAVING COUNT(1)=2
28、查询男生、女生人数
SELECT st.s_sex,COUNT(1)
FROM student st
GROUP BY st.s_sex
29、查询名字中含有"风"字的学生信息
SELECT st.*
FROM student st
WHERE st.s_name LIKE "%风%";
30、查询同名同性学生名单,并统计同名人数
SELECT st.*,COUNT(1)
FROM student st
GROUP BY st.s_name,st.s_sex HAVING COUNT(1)>1
31、查询1990年出生的学生名单
SELECT st.*
FROM student st
WHERE st.s_birth LIKE "1990%"
32、查询每门课程的平均成绩,结果按平均成绩降序排列,平均成绩相同时,按课程编号升序排列
SELECT c.c_id,c.c_name,AVG(sc.s_score)
FROM course c
INNER JOIN score sc ON sc.c_id=c.c_id
GROUP BY c.c_id ORDER BY AVG(sc.s_score) DESC,c.c_id ASC
33、查询平均成绩大于等于85的所有学生的学号、姓名和平均成绩
SELECT st.s_id,st.s_name,AVG(sc.s_score)
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id HAVING AVG(sc.s_score)>=85
34、查询课程名称为"数学",且分数低于60的学生姓名和分数
SELECT st.s_id,st.s_name,sc.s_score
FROM student st
INNER JOIN score sc ON sc.s_id=st.s_id AND sc.s_score<60
INNER JOIN course c ON c.c_id=sc.c_id AND c.c_name ="数学"
35、查询所有学生的课程及分数情况;
SELECT st.s_id,st.s_name,c.c_name,sc.s_score
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
LEFT JOIN course c ON c.c_id =sc.c_id
ORDER BY st.s_id,c.c_name
36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数
SELECT st2.s_id,st2.s_name,c2.c_name,sc2.s_score
FROM student st2
LEFT JOIN score sc2 ON sc2.s_id=st2.s_id
LEFT JOIN course c2 ON c2.c_id=sc2.c_id
WHERE st2.s_id IN(
SELECT st.s_id FROM student st
GROUP BY st.s_id HAVING sc2.s_score>=70)
ORDER BY s_id
SELECT st.s_id,st.s_name,c.c_name,sc.s_score
FROM student st
INNER JOIN score sc ON sc.s_id=st.s_id AND sc.s_score>=70
INNER JOIN course c ON c.c_id=sc.c_id
37、查询不及格的课程
SELECT st.s_id,c.c_name,st.s_name,sc.s_score
FROM student st
INNER JOIN score sc ON sc.s_id=st.s_id AND sc.s_score<60
INNER JOIN course c ON c.c_id=sc.c_id
38、查询课程编号为01且课程成绩在80分以上的学生的学号和姓名
SELECT st.s_id,st.s_name,sc.s_score
FROM student st
INNER JOIN score sc ON sc.s_id=st.s_id AND sc.c_id="01" AND sc.s_score>=80
39、求每门课程的学生人数
SELECT c.c_id,c.c_name,COUNT(1)
FROM course c
INNER JOIN score sc ON sc.c_id=c.c_id
GROUP BY c.c_id
40、查询选修"张三"老师所授课程的学生中,成绩最高的学生信息及其成绩
SELECT st.*,c.c_name,sc.s_score,t.t_name FROM student st
INNER JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id=sc.c_id
INNER JOIN teacher t ON t.t_id=c.t_id AND t.t_name="张三"
ORDER BY sc.s_score DESC
LIMIT 0,1
41、查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩
SELECT st.s_id,st.s_name,sc.c_id,sc.s_score
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
LEFT JOIN course c ON c.c_id=sc.c_id
WHERE (
SELECT COUNT(1) FROM student st2
LEFT JOIN score sc2 ON sc2.s_id=st2.s_id
LEFT JOIN course c2 ON c2.c_id=sc2.c_id
WHERE sc.s_score=sc2.s_score AND c.c_id!=c2.c_id
)>1
42、查询每门功成绩最好的前两名
SELECT a.* FROM (SELECT st.s_id,st.s_name,c.c_name,sc.s_score FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id=sc.c_id AND c.c_id="01"
ORDER BY sc.s_score DESC LIMIT 0,2) a
UNION ALL
SELECT b.* FROM (SELECT st.s_id,st.s_name,c.c_name,sc.s_score FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id=sc.c_id AND c.c_id="02"
ORDER BY sc.s_score DESC LIMIT 0,2) b
UNION ALL
SELECT c.* FROM (SELECT st.s_id,st.s_name,c.c_name,sc.s_score FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
INNER JOIN course c ON c.c_id=sc.c_id AND c.c_id="03"
ORDER BY sc.s_score DESC LIMIT 0,2) c
SELECT a.s_id,a.c_id,a.s_score
FROM score a
WHERE (SELECT COUNT(1) FROM score b WHERE b.c_id=a.c_id AND b.s_score>=a.s_score)<=2 ORDER BY a.c_id
– 43、统计每门课程的学生选修人数(超过5人的课程才统计)。要求输出课程号和选修人数,查询结果按人数降序排列,
– 若人数相同,按课程号升序排列
SELECT sc.c_id,COUNT(1)
FROM score sc
LEFT JOIN course c ON c.c_id=sc.c_id
GROUP BY c.c_id HAVING COUNT(1)>5
ORDER BY COUNT(1) DESC,sc.c_id ASC
44、检索至少选修两门课程的学生学号
SELECT st.s_id
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id HAVING COUNT(1)>=2
45、查询选修了全部课程的学生信息
SELECT st.*
FROM student st
LEFT JOIN score sc ON sc.s_id=st.s_id
GROUP BY st.s_id HAVING COUNT(1)=(SELECT COUNT(1) FROM course)