50个常用sql语句
建表：
--学生表tblStudent（编号StuId、姓名StuName、年龄StuAge、性别StuSex）
--课程表tblCourse（课程编号CourseId、课程名称CourseName、教师编号TeaId）
--成绩表tblScore（学生编号StuId、课程编号CourseId、成绩Score）
--教师表tblTeacher（教师编号TeaId、姓名TeaName）
问题：
1、查询“001”课程比“002”课程成绩高的所有学生的学号;
select a.StuId from (select StuId,Score from tblScore where CourseId='001') a,(select StuId,Score
from tblScore where CourseId='002') b
where a.Score>b.Score and a.StuId=b.StuId;
2、查询平均成绩大于60分的同学的学号和平均成绩;
select StuId,avg(Score)
from tblScore
group by StuId having avg(Score) >60;
3、查询所有同学的学号、姓名、选课数、总成绩;
select tblStudent.StuId,tblStudent.StuName,count(tblScore.CourseId),sum(Score)
from tblStudent left Outer join tblScore on tblStudent.StuId=tblScore.StuId
group by tblStudent.StuId,StuName
4、查询姓“李”的老师的个数;
select count(distinct(TeaName))
from tblTeacher
where TeaName like '李%';
5、查询没学过“叶平”老师课的同学的学号、姓名;
select tblStudent.StuId,tblStudent.StuName
from tblStudent
where StuId not in (select distinct( tblScore.StuId) from tblScore,tblCourse,tblTeacher where tblScore.CourseId=tblCourse.CourseId and tblTeacher.TeaId=tblCourse.TeaId and tblTeacher.TeaName='叶平');
6、查询学过“001”并且也学过编号“002”课程的同学的学号、姓名;
select tblStudent.StuId,tblStudent.StuName from tblStudent,tblScore where tblStudent.StuId=tblScore.StuId and tblScore.CourseId='001'and exists( Select * from tblScore as tblScore_2 where tblScore_2.StuId=tblScore.StuId and tblScore_2.CourseId='002');
7、查询学过“叶平”老师所教的所有课的同学的学号、姓名;
select StuId,StuName
from tblStudent
where StuId in (select StuId from tblScore ,tblCourse ,tblTeacher where tblScore.CourseId=tblCourse.CourseId and tblTeacher.TeaId=tblCourse.TeaId and tblTeacher.TeaName='叶平' group by StuId having count(tblScore.CourseId)=(select count(CourseId) from tblCourse,tblTeacher where tblTeacher.TeaId=tblCourse.TeaId and TeaName='叶平'));
8、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;
Select StuId,StuName from (select tblStudent.StuId,tblStudent.StuName,Score ,(select Score from tblScore tblScore_2 where tblScore_2.StuId=tblStudent.StuId and tblScore_2.CourseId='002') Score2
from tblStudent,tblScore where tblStudent.StuId=tblScore.StuId and CourseId='001') S_2 where Score2 <Score;
9、查询所有课程成绩小于60分的同学的学号、姓名;
select StuId,StuName
from tblStudent
where StuId not in (select tblStudent.StuId from tblStudent,tblScore where S.StuId=tblScore.StuId and Score>60);
10、查询没有学全所有课的同学的学号、姓名;
select tblStudent.StuId,tblStudent.StuName
from tblStudent,tblScore
where tblStudent.StuId=tblScore.StuId group by tblStudent.StuId,tblStudent.StuName having count(CourseId) <(select count(CourseId) from tblCourse);
11、查询至少有一门课与学号为“1001”的同学所学相同的同学的学号和姓名;
select StuId,StuName from tblStudent,tblScore where tblStudent.StuId=tblScore.StuId and CourseId in select CourseId from tblScore where StuId='1001';
12、查询至少学过学号为“001”同学所有一门课的其他同学学号和姓名;
select distinct tblScore.StuId,StuName
from tblStudent,tblScore
where tblStudent.StuId=tblScore.StuId and CourseId in (select CourseId from tblScore where StuId='001');
13、把“tblScore”表中“叶平”老师教的课的成绩都更改为此课程的平均成绩;
update tblScore set Score=(select avg(tblScore_2.Score)
from tblScore tblScore_2
where tblScore_2.CourseId=tblScore.CourseId ) from tblCourse,tblTeacher where tblCourse.CourseId=tblScore.CourseId and tblCourse.TeaId=tblTeacher.TeaId and tblTeacher.TeaName='叶平');
14、查询和“1002”号的同学学习的课程完全相同的其他同学学号和姓名;
select StuId from tblScore where CourseId in (select CourseId from tblScore where StuId='1002')
group by StuId having count(*)=(select count(*) from tblScore where StuId='1002');
15、删除学习“叶平”老师课的tblScore表记录;
Delect tblScore
from tblCourse ,tblTeacher
where tblCourse.CourseId=tblScore.CourseId and tblCourse.TeaId= tblTeacher.TeaId and TeaName='叶平';
16、向tblScore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“003”课程的同学学号、2、
号课的平均成绩;
Insert tblScore select StuId,'002',(Select avg(Score)
from tblScore where CourseId='002') from tblStudent where StuId not in (Select StuId from tblScore where CourseId='002');
17、按平均成绩从高到低显示所有学生的“数据库”、“企业管理”、“英语”三门的课程成绩，按如下形式显示： 学生ID,,数据库,企业管理,英语,有效课程数,有效平均分
SELECT StuId as 学生ID
,(SELECT Score FROM tblScore WHERE tblScore.StuId=t.StuId AND CourseId='004') AS 数据库
,(SELECT Score FROM tblScore WHERE tblScore.StuId=t.StuId AND CourseId='001') AS 企业管理
,(SELECT Score FROM tblScore WHERE tblScore.StuId=t.StuId AND CourseId='006') AS 英语
,COUNT(*) AS 有效课程数, AVG(t.Score) AS 平均成绩
FROM tblScore AS t
GROUP BY StuId
ORDER BY avg(t.Score)
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
SELECT L.CourseId As 课程ID,L.Score AS 最高分,R.Score AS 最低分
FROM tblScore L ,tblScore AS R
WHERE L.CourseId = R.CourseId and
L.Score = (SELECT MAX(IL.Score)
FROM tblScore AS IL,tblStudent AS IM
WHERE L.CourseId = IL.CourseId and IM.StuId=IL.StuId
GROUP BY IL.CourseId)
AND
R.Score = (SELECT MIN(IR.Score)
FROM tblScore AS IR
WHERE R.CourseId = IR.CourseId
GROUP BY IR.CourseId
);
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
SELECT t.CourseId AS 课程号,max(tblCourse.CourseName)AS 课程名,isnull(AVG(Score),0) AS 平均成绩
,100 * SUM(CASE WHEN isnull(Score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数
FROM tblScore T,tblCourse
where t.CourseId=tblCourse.CourseId
GROUP BY t.CourseId
ORDER BY 100 * SUM(CASE WHEN isnull(Score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) DESC
20、查询如下课程平均成绩和及格率的百分数(用"1行"显示): 企业管理（001），马克思（002），OO&UML （003），数据库（004）
SELECT SUM(CASE WHEN CourseId ='001' THEN Score ELSE 0 END)/SUM(CASE CourseId WHEN '001' THEN 1 ELSE 0 END) AS 企业管理平均分
,100 * SUM(CASE WHEN CourseId = '001' AND Score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CourseId = '001' THEN 1 ELSE 0 END) AS 企业管理及格百分数
,SUM(CASE WHEN CourseId = '002' THEN Score ELSE 0 END)/SUM(CASE CourseId WHEN '002' THEN 1 ELSE 0 END) AS 马克思平均分
,100 * SUM(CASE WHEN CourseId = '002' AND Score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CourseId = '002' THEN 1 ELSE 0 END) AS 马克思及格百分数
,SUM(CASE WHEN CourseId = '003' THEN Score ELSE 0 END)/SUM(CASE CourseId WHEN '003' THEN 1 ELSE 0 END) AS UML平均分
,100 * SUM(CASE WHEN CourseId = '003' AND Score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CourseId = '003' THEN 1 ELSE 0 END) AS UML及格百分数
,SUM(CASE WHEN CourseId = '004' THEN Score ELSE 0 END)/SUM(CASE CourseId WHEN '004' THEN 1 ELSE 0 END) AS 数据库平均分
,100 * SUM(CASE WHEN CourseId = '004' AND Score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CourseId = '004' THEN 1 ELSE 0 END) AS 数据库及格百分数
FROM tblScore
21、查询不同老师所教不同课程平均分从高到低显示
SELECT max(Z.TeaId) AS 教师ID,MAX(Z.TeaName) AS 教师姓名,C.CourseId AS 课程ＩＤ,MAX(C.CourseName) AS 课程名称,AVG(Score) AS 平均成绩
FROM tblScore AS T,tblCourse AS C ,tblTeacher AS Z
where T.CourseId=C.CourseId and C.TeaId=Z.TeaId
GROUP BY C.CourseId
ORDER BY AVG(Score) DESC
22、查询如下课程成绩第 3 名到第 6 名的学生成绩单：企业管理（001），马克思（002），UML （003），数据库（004）
[学生ID],[学生姓名],企业管理,马克思,UML,数据库,平均成绩
SELECT DISTINCT top 3
tblScore.StuId As 学生学号,
tblStudent.StuName AS 学生姓名 ,
T1.Score AS 企业管理,
T2.Score AS 马克思,
T3.Score AS UML,
T4.Score AS 数据库,
ISNULL(T1.Score,0) + ISNULL(T2.Score,0) + ISNULL(T3.Score,0) + ISNULL(T4.Score,0) as 总分
FROM tblStudent,tblScore LEFT JOIN tblScore AS T1
ON tblScore.StuId = T1.StuId AND T1.CourseId = '001'
LEFT JOIN tblScore AS T2
ON tblScore.StuId = T2.StuId AND T2.CourseId = '002'
LEFT JOIN tblScore AS T3
ON tblScore.StuId = T3.StuId AND T3.CourseId = '003'
LEFT JOIN tblScore AS T4
ON tblScore.StuId = T4.StuId AND T4.CourseId = '004'
WHERE tblStudent.StuId=tblScore.StuId and
ISNULL(T1.Score,0) + ISNULL(T2.Score,0) + ISNULL(T3.Score,0) + ISNULL(T4.Score,0)
NOT IN
(SELECT
DISTINCT
TOP 15 WITH TIES
ISNULL(T1.Score,0) + ISNULL(T2.Score,0) + ISNULL(T3.Score,0) + ISNULL(T4.Score,0)
FROM tblScore
LEFT JOIN tblScore AS T1
ON tblScore.StuId = T1.StuId AND T1.CourseId = 'k1'
LEFT JOIN tblScore AS T2
ON tblScore.StuId = T2.StuId AND T2.CourseId = 'k2'
LEFT JOIN tblScore AS T3
ON tblScore.StuId = T3.StuId AND T3.CourseId = 'k3'
LEFT JOIN tblScore AS T4
ON tblScore.StuId = T4.StuId AND T4.CourseId = 'k4'
ORDER BY ISNULL(T1.Score,0) + ISNULL(T2.Score,0) + ISNULL(T3.Score,0) + ISNULL(T4.Score,0) DESC);
23、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 tblScore.CourseId as 课程ID, CourseName as 课程名称
,SUM(CASE WHEN Score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85]
,SUM(CASE WHEN Score BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 - 70]
,SUM(CASE WHEN Score BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 - 60]
,SUM(CASE WHEN Score < 60 THEN 1 ELSE 0 END) AS [60 -]
FROM tblScore,tblCourse
where tblScore.CourseId=tblCourse.CourseId
GROUP BY tblScore.CourseId,CourseName;
24、查询学生平均成绩及其名次
SELECT 1+(SELECT COUNT( distinct 平均成绩)
FROM (SELECT StuId,AVG(Score) AS 平均成绩
FROM tblScore
GROUP BY StuId
) AS T1
WHERE 平均成绩 > T2.平均成绩) as 名次,
StuId as 学生学号,平均成绩
FROM (SELECT StuId,AVG(Score) 平均成绩
FROM tblScore
GROUP BY StuId
) AS T2
ORDER BY 平均成绩 desc;
25、查询各科成绩前三名的记录:(不考虑成绩并列情况)
SELECT t1.StuId as 学生ID,t1.CourseId as 课程ID,Score as 分数
FROM tblScore t1
WHERE Score IN (SELECT TOP 3 Score
FROM tblScore
WHERE t1.CourseId= CourseId
ORDER BY Score DESC
)
ORDER BY t1.CourseId;
26、查询每门课程被选修的学生数
select CourseId,count(StuId) from tblScore group by CourseId;
27、查询出只选修了一门课程的全部学生的学号和姓名
select tblScore.StuId,tblStudent.StuName,count(CourseId) AS 选课数
from tblScore ,tblStudent
where tblScore.StuId=tblStudent.StuId group by tblScore.StuId ,tblStudent.StuName having count(CourseId)=1;
28、查询男生、女生人数
Select count(StuSex) as 男生人数 from tblStudent group by StuSex having StuSex='男';
Select count(StuSex) as 女生人数 from tblStudent group by StuSex having StuSex='女';
29、查询姓“张”的学生名单
SELECT StuName FROM tblStudent WHERE StuName like '张%';
30、查询同名同性学生名单，并统计同名人数
select StuName,count(*) from tblStudent group by StuName having count(*)>1;;
31、1981年出生的学生名单(注：tblStudent表中StuAge列的类型是datetime)
select StuName, CONVERT(char (11),DATEPART(year,StuAge)) as age
from tblStudent
where CONVERT(char(11),DATEPART(year,StuAge))='1981';
32、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 CourseId,Avg(Score) from tblScore group by CourseId order by Avg(Score),CourseId DESC ;
33、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 StuName,tblScore.StuId ,avg(Score)
from tblStudent,tblScore
where tblStudent.StuId=tblScore.StuId group by tblScore.StuId,StuName having avg(Score)>85;
34、查询课程名称为“数据库”，且分数低于60的学生姓名和分数
Select StuName,isnull(Score,0)
from tblStudent,tblScore,tblCourse
where tblScore.StuId=tblStudent.StuId and tblScore.CourseId=tblCourse.CourseId and tblCourse.CourseName='数据库'and Score <60;
35、查询所有学生的选课情况;
SELECT tblScore.StuId,tblScore.CourseId,StuName,CourseName
FROM tblScore,tblStudent,tblCourse
where tblScore.StuId=tblStudent.StuId and tblScore.CourseId=tblCourse.CourseId ;
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 distinct tblStudent.StuId,tblStudent.StuName,tblScore.CourseId,tblScore.Score
FROM tblStudent,tblScore
WHERE tblScore.Score>=70 AND tblScore.StuId=tblStudent.StuId;
37、查询不及格的课程，并按课程号从大到小排列
select CourseId from tblScore where scor e <60 order by CourseId ;
38、查询课程编号为003且课程成绩在80分以上的学生的学号和姓名;
select tblScore.StuId,tblStudent.StuName from tblScore,tblStudent where tblScore.StuId=tblStudent.StuId and Score>80 and CourseId='003';
39、求选了课程的学生人数
select count(*) from tblScore;
40、查询选修“叶平”老师所授课程的学生中，成绩最高的学生姓名及其成绩
select tblStudent.StuName,Score
from tblStudent,tblScore,tblCourse C,tblTeacher
where tblStudent.StuId=tblScore.StuId and tblScore.CourseId=C.CourseId and C.TeaId=tblTeacher.TeaId and tblTeacher.TeaName='叶平' and tblScore.Score=(select max(Score)from tblScore where CourseId=C.CourseId );
41、查询各个课程及相应的选修人数
select count(*) from tblScore group by CourseId;
42、查询不同课程成绩相同的学生的学号、课程号、学生成绩
select distinct A.StuId,B.Score from tblScore A ,tblScore B where A.Score=B.Score and A.CourseId <>B.CourseId ;
43、查询每门功成绩最好的前两名
SELECT t1.StuId as 学生ID,t1.CourseId as 课程ID,Score as 分数
FROM tblScore t1
WHERE Score IN (SELECT TOP 2 Score
FROM tblScore
WHERE t1.CourseId= CourseId
ORDER BY Score DESC
)
ORDER BY t1.CourseId;
44、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，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 CourseId as 课程号,count(*) as 人数
from tblScore
group by CourseId
order by count(*) desc,CourseId
45、检索至少选修两门课程的学生学号
select StuId
from tblScore
group by StuId
having count(*) > = 2
46、查询全部学生都选修的课程的课程号和课程名
select CourseId,CourseName
from tblCourse
where CourseId in (select CourseId from tblScore group by CourseId)
47、查询没学过“叶平”老师讲授的任一门课程的学生姓名
select StuName from tblStudent where StuId not in (select StuId from tblCourse,tblTeacher,tblScore where tblCourse.TeaId=tblTeacher.TeaId and tblScore.CourseId=tblCourse.CourseId and TeaName='叶平');
48、查询两门以上不及格课程的同学的学号及其平均成绩
select StuId,avg(isnull(Score,0)) from tblScore where StuId in (select StuId from tblScore where Score <60 group by StuId having count(*)>2)group by StuId;
49、检索“004”课程分数小于60，按分数降序排列的同学学号
select StuId from tblScore where CourseId='004'and Score <60 order by Score desc;
50、删除“002”同学的“001”课程的成绩
delete from tblScore where StuId='001'and CourseId='001';