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创建表及其插入数据

建表

/**学生表*/
CREATE TABLE student(
sno VARCHAR(10) PRIMARY KEY,
sname VARCHAR(20),
sage NUMERIC(2),
ssex VARCHAR(5)
);

/**老师表*/
CREATE TABLE teacher(
tno VARCHAR(10) PRIMARY KEY,
tname VARCHAR(20)
);

/**课程表*/
CREATE TABLE course(
cno VARCHAR(10),
cname VARCHAR(20),
tno VARCHAR(20),
CONSTRAINT pk_course PRIMARY KEY (cno,tno)
);

/**成绩表*/
CREATE TABLE sc(
sno VARCHAR(10),
cno VARCHAR(10),
score NUMERIC(4,2),
CONSTRAINT pk_sc PRIMARY KEY (sno,cno)
);

插入数据

/*******初始化学生表的数据******/
insert into student values ('s001','张三',23,'男'); 
insert into student values ('s002','李四',23,'男'); 
insert into student values ('s003','吴鹏',25,'男'); 
insert into student values ('s004','琴沁',20,'女'); 
insert into student values ('s005','王丽',20,'女'); 
insert into student values ('s006','李波',21,'男'); 
insert into student values ('s007','刘玉',21,'男'); 
insert into student values ('s008','萧蓉',21,'女');
insert into student values ('s009','陈萧晓',23,'女');
insert into student values ('s010','陈美',22,'女');
insert into student values ('s011','陈美',38,'女');
commit;
/******************初始化教师表***********************/
insert into teacher values ('t001', '刘阳'); 
insert into teacher values ('t002', '谌燕'); 
insert into teacher values ('t003', '胡明星'); 
commit; );
/***************初始化课程表****************************/
insert into course values ('c001','J2SE','t002');
insert into course values ('c002','Java Web','t002');
insert into course values ('c003','SSH','t001'); 
insert into course values ('c004','Oracle','t001'); 
insert into course values ('c005','SQL SERVER 2005','t003'); 
insert into course values ('c006','C#','t003'); 
insert into course values ('c007','JavaScript','t002'); 
insert into course values ('c008','DIV+CSS','t001'); 
insert into course values ('c009','PHP','t003');
insert into course values ('c010','EJB3.0','t002');
commit;
/***************初始化成绩表***********************/
insert into sc values ('s001','c001',78.9);
insert into sc values ('s002','c001',80.9); 
insert into sc values ('s003','c001',81.9); 
insert into sc values ('s004','c001',60.9); 
insert into sc values ('s001','c002',82.9); 
insert into sc values ('s002','c002',72.9); 
insert into sc values ('s003','c002',81.9); 
insert into sc values ('s001','c003','59'); 
insert into sc values ('s002','c003','59'); 
insert into sc values ('s004','c004','59'); 
insert into sc values ('s001','c004','59'); 
insert into sc values ('s005','c004','59'); 
insert into sc values ('s006','c004','52'); 
insert into sc values ('s007','c004','62'); 
commit;

sql题50道

1、查询“c001”课程比“c002”课程成绩高的所有学生的学号；

SELECT s.sno from  sc  s  INNER JOIN sc c ON s.sno=c.sno
where s.cno='c001'
	and c.cno='c002'
  	 and c.score<s.score

2、查询平均成绩大于60 分的同学的学号和平均成绩；

	SELECT sno,avg(score) from sc 
	GROUP BY sno
	HAVING avg(score)>60

3、查询所有同学的学号、姓名、选课数、总成绩；

SELECT s.sno,sname,COUNT(cno),SUM(score) from student s
INNER JOIN sc  c ON s.sno=c.sno
GROUP BY s.sno

4、查询姓“刘”的老师的个数；

SELECT COUNT(tno) from  teacher 
where tname LIKE '刘%'

5、查询没学过“谌燕”老师课的同学的学号、姓名；

SELECT DISTINCT s.sno,sname from student s 
where s.sno not in(
SELECT  DISTINCT s.sno  from student s 
 INNER JOIN sc c 				on s.sno=c.sno
 INNER JOIN course co           on c.cno=co.cno
 INNER JOIN teacher t    	    on co.tno=t.tno
where t.tname='谌燕'
)

6、查询学过“c001”并且也学过编号“c002”课程的同学的学号、姓名

SELECT s.sno,sname from student s 
INNER JOIN sc c ON s.sno=c.sno
INNER JOIN sc c1 ON c.sno=c1.sno
where c.cno='c001'
	  and c1.cno='c002'

7、查询学过“谌燕”老师所教的课的同学的学号、姓名；

SELECT  DISTINCT s.sno,sname  from student s 
 INNER JOIN sc c 				on s.sno=c.sno
 INNER JOIN course co           on c.cno=co.cno
 INNER JOIN teacher t           on co.tno=t.tno
where t.tname='谌燕'

8、查询课程编号“c002”的成绩比课程编号“c001”课程低的所有同学的学号、姓名；

SELECT s.sno,sname from student s
INNER JOIN sc c on c.sno=s.sno
INNER JOIN sc c1 on c.sno =c1.sno
where 
	c.cno='c001'
    and c1.cno='c002'
	AND c1.score<c.score

9、查询所有课程成绩小于60 分的同学的学号、姓名；

SELECT DISTINCT s.sno,sname from student s
INNER JOIN sc c on s.sno =c.sno
where score<60

10、查询没有学全所有课的同学的学号、姓名；

SELECT s.sno,sname from student s  INNER JOIN sc  c ON s.sno=c.sno
GROUP BY s.sno
HAVING COUNT(c.cno)<(SELECT COUNT(*) from course)

11、查询至少有一门课与学号为“s001”的同学所学相同的同学的学号和姓名；

/**多表查询*/
SELECT DISTINCT s.sno,sname from student s 
	INNER JOIN sc c on  s.sno=c.sno
		where cno in (
			SELECT cno from sc 
			where sno='s001'
		)
AND s.sno !='s001'

12、查询至少学过学号为“s001”同学所有一门课的其他同学学号和姓名；

/*嵌套子查询*/
  Select s.sno,sname From student s
		Where s.sno In(
			Select Distinct sno From sc 
					Where cno Not In (
							Select cno From sc 
							Where sno='1001'
						 )
		)
AND s.sno !='s001'

13、把“SC”表中“谌燕”老师教的课的成绩都更改为此课程的平均成绩；

update sc s INNER JOIN (
	select cno,AVG(score) score from sc where cno in (
		select c.cno from course c join teacher t on c.tno=t.tno
				where t.TName='谌燕'
	) group by cno
)t on s.cno=t.cno set s.score=t.score

14、查询和“s001”号的同学学习的课程完全相同的其他同学学号和姓名；

  Select sno,sname From student 
		Where sno In(	
				Select   sno From sc 
						Where cno In (
								Select cno From sc 
											Where sno='s001'
						 )
				GROUP BY sno
				HAVING COUNT(*)=(SELECT count(cno) from sc where sno='s001')	
		)
AND sno!='s001'

15、删除学习“谌燕”老师课的SC 表记录；

DELETE from sc where cno in (
select cno from course
where tno=(select tno from teacher
where tname='谌燕')
) 

16、向SC 表中插入一些记录，这些记录要求符合以下条件：没有上过编号“c002”课程的同学学号、“c002”号课的平均成绩；

17、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

SELECT cno as '课程ID',MAX(score) as '最高分', MIN(score) as '最低分' from sc 
GROUP BY cno

18、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

SELECT cno,AVG(score),(100*sum(case when sc.score>=60 then 1 else 0 end)/count(1)||'%') from sc 
GROUP BY cno
ORDER BY AVG(score) 
AND  sum(case when sc.score>=60 then 1 else 0 end)/count(1) desc

19、查询不同老师所教不同课程平均分从高到低显示

SELECT c.tno,c.cno,AVG(score) from sc s 
INNER JOIN course c  on s.cno=c.cno
GROUP BY c.cno
ORDER BY AVG(score) DESC

20、统计列印各科成绩,各分数段人数:课程ID,课程名称,[100-85],[85-70],[70-60],[ <60]

select c.cno,cname,
count(case when score between 85 and 100 then 1 end) as '85-100分',
count(case when score between 70 and 85 then 1 end) as '70-85分',
count(case when score between 60 and 70 then 1 end) as '60-70分',
count(case when score<60 then 1 end) as '60分以下'
from sc INNER JOIN course c on sc.cno=c.cno
GROUP BY c.cno

21、查询各科成绩前三名的记录:(不考虑成绩并列情况)

SELECT s1.* FROM sc s1 WHERE
(
SELECT COUNT(*) FROM sc s2 WHERE
s1.cno=s2.cno AND s2.score>=s1.score
)<=3
ORDER BY s1.cno,s1.score DESC;

22、查询每门课程被选修的学生数

SELECT cno as '课程号',COUNT(cno) as '人数' from sc 
GROUP BY cno

23、查询出只选修了一门课程的全部学生的学号和姓名

SELECT sno,sname from student 
where sno in (
 SELECT sno from sc
 GROUP BY sno
 HAVING COUNT(cno)=1
)

24、查询男生、女生人数

SELECT ssex as '性别',COUNT(*) from student 
GROUP BY ssex

25、查询姓“张”的学生名单

SELECT * from student where sname like '张%'

26、查询同名同姓学生名单，并统计同名人数

SELECT sname,COUNT(sno) as '同名人数' from student 
GROUP BY sname
HAVING count(sno)>=2

27、1981 年出生的学生名单(注：Student 表中Sage 列的类型是number)

/*year(now())为获得当前年*/
/*month(now())为获得当前月*/
/*day(now())为获得当前天*/
SELECT * from student 
where year(now())-sage=1981

28、查询每门课程的平均成绩，结果按平均成绩升序排列，平均成绩相同时，按课程号降序排列

SELECT cno,avg(score) from sc 
GROUP BY cno
ORDER BY avg(score)
and  cno DESC

29、查询平均成绩大于85 的所有学生的学号、姓名和平均成绩

SELECT s.sno,sname,avg(score) as '平均成绩' from student s 
INNER JOIN sc c on s.sno=c.sno
GROUP BY sno
HAVING avg(score)>60

30、查询课程名称为“Oracle”，且分数低于60 的学生姓名和分数

SELECT sname,score from student st 
INNER JOIN sc s on st.sno=s.sno
INNER JOIN course c on s.cno=c.cno
where cname='Oracle'
AND score <60

31、查询所有学生的选课情况；

SELECT sno,COUNT(cno) as '选课数量' from sc
GROUP BY sno

32、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 sname,cname,score from sc s
INNER JOIN student t on s.sno=t.sno
INNER JOIN course  c on s.cno=c.cno
where score>70

33、查询不及格的课程，并按课程号从大到小排列

SELECT DISTINCT cno from sc 
where score<60
ORDER BY cno DESC

34、查询课程编号为c001 且课程成绩在80 分以上的学生的学号和姓名；

SELECT s.sno,sname from sc s
INNER JOIN student t on s.sno=t.sno
where cno='c001'
AND score>80

35、求选了课程的学生人数

SELECT COUNT(DISTINCT sno) as '选修课程' from sc 

36、查询选修“谌燕”老师所授课程的学生中，成绩最高的学生姓名及其成绩

SELECT s.cno,sname,MAX(score) from student st 
INNER JOIN sc s on st.sno=s.sno
INNER JOIN course c on s.cno=c.cno
INNER JOIN teacher t on c.tno=t.tno
where tname='谌燕'
GROUP BY s.cno

37、查询各个课程及相应的选修人数

SELECT cno,COUNT(sno) as '选课人数' from sc 
GROUP BY cno

38、查询不同课程成绩相同的学生的学号、课程号、学生成绩

SELECT s.sno,s.cno,s.score from sc s
INNER JOIN sc c on s.sno=c.sno
where s.cno!=c.cno
AND s.score=c.score 

39、查询每门功课成绩最好的前两名

SELECT s1.* FROM sc s1 WHERE
(
SELECT COUNT(*) FROM sc s2 WHERE
s1.cno=s2.cno AND s2.score>=s1.score
)<=2
ORDER BY s1.cno,s1.score DESC;

40、统计每门课程的学生选修人数（超过10 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 cno,COUNT(sno) from sc
GROUP BY cno
HAVING COUNT(sno)>1
ORDER BY COUNT(sno) DESC 

41、检索至少选修两门课程的学生学号

SELECT sno from sc 
GROUP BY sno
HAVING COUNT(cno)>=2

42、查询全部学生都选修的课程的课程号和课程名

SELECT t.sno,sname,s.cno,cname from student t
INNER JOIN sc s on t.sno =s.sno
INNER JOIN course c on s.cno =c.cno 

43、查询没学过“谌燕”老师讲授的任一门课程的学生姓名

SELECT sname from student 
where sno not in (
SELECT DISTINCT s.sno from sc s 
INNER JOIN course c on s.cno=c.cno
INNER JOIN teacher t on c.tno=t.tno
where tname='谌燕'
)

44、查询两门以上不及格课程的同学的学号及其平均成绩

SELECT sno,AVG(score) from sc 
where sno in(
SELECT sno from sc 
where score<60
GROUP BY sno
HAVING COUNT(score)>=2
)

45、检索“c004”课程分数小于60，按分数降序排列的同学学号

SELECT sno /*cno,score,测试时候加上便于查看***/from sc 
where cno='c004'
AND score<60
ORDER BY score DESC

46、删除“s002”同学的“c001”课程的成绩

DELETE from sc where sno='s002'
AND cno='c001'
``