常用SQL语句积累---
一、常用的语句格式积累：
Select top 3 * from class order by id desc 表示查询前3条的数据并且按降来排
select distinct 年龄 from class 去除重复行的查询select * from class order by 名字 collate chinese_prc_cs_as 按音序查询
二、常用的例子收集--
Student(S#,Sname,Sage,Ssex)学生表
Course(C#,Cname,T#) 课程表
SC(S#,C#,score) 成绩表
Teacher(T#,Tname) 教师表
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.S# from (select s#,scorefrom SC whereC#='001') a,(selects#,score
from SC where C#='002')b
where a.score>b.scoreand a.s#=b.s#;
2、查询平均成绩大于60分的同学的学号和平均成绩；
select S#,avg(score)
from sc
group by S# having avg(score) >60;
3、查询所有同学的学号、姓名、选课数、总成绩；
select Student.S#,Student.Sname,count(SC.C#),sum(score)
from Student leftOuter join SC on Student.S#=SC.S#
group by Student.S#,Sname
4、查询姓“李”的老师的个数；
select count(distinct(Tname))
from Teacher
where Tname like'李%';
5、查询没学过“叶平”老师课的同学的学号、姓名；
Student.S#,Student.Sname
from Student
where S# not in (select distinct( SC.S#)fromSC,Course,Teacher where SC.C#=Course.C#andTeacher.T#=Course.T#and Teacher.Tname='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 Student.S#,Student.Sname fromStudent,SC where Student.S#=SC.S#andSC.C#='001'andexists( Select * from SC as SC_2where SC_2.S#=SC.S#andSC_2.C#='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 S#,Sname
from Student
where S# in (select S#from SC ,Course ,Teacher where SC.C#=Course.C#and Teacher.T#=Course.T#andTeacher.Tname='叶平'groupby S# having count(SC.C#)=(selectcount(C#) from
Course,Teacher whereTeacher.T#=Course.T#and Tname='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 S#,Sname from (selectStudent.S#,Student.Sname,score ,(select scorefrom SC SC_2 whereSC_2.S#=Student.S#and SC_2.C#='002') score2
from Student,SC where Student.S#=SC.S#andC#='001') S_2wherescore2 <score;
9、查询所有课程成绩小于60分的同学的学号、姓名；
select S#,Sname
from Student
where S# not in (select Student.S# from Student,SC whereS.S#=SC.S#and score>60);
10、查询没有学全所有课的同学的学号、姓名；
select Student.S#,Student.Sname
from Student,SC
where Student.S#=SC.S#groupby Student.S#,Student.Snamehaving count(C#)<(select count(C#) from Course);
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 S#,Sname from Student,SCwhereStudent.S#=SC.S#and C# in select C# from SC where S#='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 SC.S#,Sname
from Student,SC
where Student.S#=SC.S#andC# in (select C#from SC where S#='001');
13、把“SC”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 SC set score=(selectavg(SC_2.score)
from SC SC_2
where SC_2.C#=SC.C# )fromCourse,Teacher where Course.C#=SC.C#andCourse.T#=Teacher.T#and Teacher.Tname='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 S# from SCwhere C# in (select C#from SC where S#='1002')
group by
S# havingcount(*)=(selectcount(*) from SC where S#='1002');
15、删除学习“叶平”老师课的SC表记录；
Delect SC
from course ,Teacher
where Course.C#=SC.C#andCourse.T#= Teacher.T#and Tname='叶平';
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“003”课程的同学学号、2、
号课的平均成绩；
Insert SC select S#,'002',(Selectavg(score)
from SC where C#='002')from Studentwhere S# not in (Select S# from SCwhere C#='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 S# as 学生ID
,(SELECT score FROMSCWHERE SC.S#=t.S# AND C#='004')AS 数据库
,(SELECT score FROM SCWHERE SC.S#=t.S# AND C#='001')AS 企业管理
,(SELECT score FROMSCWHERE SC.S#=t.S# AND C#='006')AS 英语
,COUNT(*)AS 有效课程数,AVG(t.score)AS 平均成绩
FROM SC AS t
GROUP BY S#
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.C# As 课程ID,L.scoreAS 最高分,R.scoreAS 最低分
FROM SC L ,SC AS R
WHERE L.C# = R.C#and
L.score = (SELECTMAX(IL.score)
FROM SC AS IL,Student AS IM
WHERE L.C# = IL.C# and IM.S#=IL.S#
GROUP BY IL.C#)
AND
R.Score
= (SELECT MIN(IR.score)
FROM SC AS IR
WHERE R.C# = IR.C#
GROUP BY IR.C#
);
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.C# AS 课程号,max(course.Cname)AS 课程名,isnull(AVG(score),0)AS 平均成绩
,100 * SUM(CASEWHEN isnull(score,0)>=60THEN 1ELSE0 END)/COUNT(*)AS 及格百分数
FROM SC T,Course
where t.C#=course.C#
GROUP BY t.C#
ORDER BY 100 * SUM(CASE WHEN isnull(score,0)>=60THEN 1ELSE
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(CASEWHEN C# ='001'THENscore ELSE 0 END)/SUM(CASEC#WHEN '001' THEN 1 ELSE 0 END) AS 企业管理平均分
,100 * SUM(CASEWHEN C#= '001' AND score >= 60THEN 1ELSE 0END)/SUM(CASEWHEN C#= '001' THEN 1 ELSE 0 END
) AS 企业管理及格百分数
,SUM(CASEWHEN C#= '002' THEN score ELSE 0END)/SUM(CASEC#WHEN '002' THEN 1 ELSE 0 END) AS 马克思平均分
,100 * SUM(CASEWHEN C#= '002' AND score >= 60THEN 1ELSE 0END)/SUM(CASEWHEN C#= '002' THEN 1 ELSE 0 END) AS 马克思及格百分数
,SUM(CASEWHEN C#= '003' THEN score ELSE 0END)/
SUM(CASE C#WHEN '003' THEN 1 ELSE 0 END) AS UML平均分
,100 * SUM(CASEWHEN C#= '003' AND score >= 60THEN 1ELSE 0END)/SUM(CASEWHEN C#= '003' THEN 1 ELSE 0 END) AS UML及格百分数
,SUM(CASEWHEN C#= '004' THEN score ELSE 0END)/SUM(CASEC#WHEN '004' THEN 1 ELSE 0 END) AS 数据库平均分
,100
* SUM(CASEWHEN C# = '004' AND score >=60 THEN1 ELSE0 END)/SUM(CASEWHEN C#= '004' THEN 1 ELSE 0 END) AS 数据库及格百分数
FROM SC
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.T#)AS 教师ID,MAX(Z.Tname)AS 教师姓名,C.C#AS 课程ＩＤ,MAX(C.Cname)AS 课程名称,AVG(Score)AS 平均成绩
FROM SC AS T,CourseAS C ,Teacher AS Z
where T.C#=C.C#and C.T#=Z.T#
GROUP BY C.C#
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 DISTINCTtop 3
SC.S# As 学生学号,
Student.Sname 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 Student,SC LEFTJOINSC AS T1
ON SC.S# = T1.S# AND T1.C# = '001'
LEFT JOINSCAS T2
ON SC.S# = T2.S# AND T2.C# = '002'
LEFT JOINSCAS T3
ON SC.S# =T3.S# AND T3.C# = '003'
LEFT JOINSCAS T4
ON SC.S# = T4.S# AND T4.C# = '004'
WHERE student.S#=SC.S#and
ISNULL(T1.score,0)+ ISNULL(T2.score,0)+ ISNULL(T3.score,0)+ ISNULL(T4.score,0)
NOT IN
(SELECT
DISTINCT
TOP 15WITH TIES
ISNULL(T1.score,0)+ ISNULL(T2.score,0)+ ISNULL(T3.score,0)+ ISNULL(T4.score,0)
FROM sc
LEFT JOINscAS T1
ON sc.S# = T1.S# AND T1.C#='k1'
LEFT JOINscAS T2
ON sc.S# = T2.S# AND T2.C# = 'k2'
LEFT JOINscAS T3
ON sc.S# = T3.S# AND T3.C# = 'k3'
LEFT JOINscAS T4
ON sc.S# = T4.S# AND T4.C# = '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 SC.C# as 课程ID,Cname
as 课程名称
,SUM(CASEWHEN scoreBETWEEN 85AND 100THEN 1ELSE 0END) AS [100- 85]
,SUM(CASEWHEN scoreBETWEEN 70AND 85THEN 1ELSE 0END) AS [85 -70]
,SUM(CASEWHEN scoreBETWEEN 60AND 70THEN 1ELSE 0END) AS [70 -60]
,SUM(CASEWHEN score< 60THEN 1ELSE 0END) AS [60-]
FROM SC,Coursewhere SC.C#=Course.C#
GROUP BY SC.C#,Cname;
24、查询学生平均成绩及其名次
SELECT 1+(SELECTCOUNT(distinct 平均成绩)
FROM(SELECT S#,AVG(score)AS 平均成绩
FROM SC
GROUP BY S#
) AS T1
WHERE平均成绩 > T2.平均成绩)as 名次,
S# as 学生学号,平均成绩
FROM (SELECT S#,AVG(score) 平均成绩
FROMSC
GROUP BY S#
) 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.S# as 学生ID,t1.C#as 课程ID,Scoreas 分数
FROM SC t1
WHERE score IN (SELECTTOP 3score
FROMSC
WHEREt1.C#= C# ORDER BY score DESC
)
ORDER BY t1.C#;
26、查询每门课程被选修的学生数
select c#,count(S#)from sc group by C#;
27、查询出只选修了一门课程的全部学生的学号和姓名
select SC.S#,Student.Sname,count(C#)AS 选课数
from SC ,Student
where SC.S#=Student.S#group bySC.S# ,Student.Snamehaving count(C#)=1;
28、查询男生、女生人数
Select count(Ssex)as 男生人数 fromStudentgroup by Ssex having Ssex='男';
Select count(Ssex)as 女生人数 fromStudentgroup by Ssex having Ssex='女'；
29、查询姓“张”的学生名单
SELECT Sname FROM StudentWHERESname like '张%';
30、查询同名同性学生名单，并统计同名人数
select Sname,count(*)fromStudentgroup by Sname having count(*)>1;;
31、1981年出生的学生名单(注：Student表中Sage列的类型是datetime)
select Sname, CONVERT(char(11),DATEPART(year,Sage))as age
from student
where CONVERT(char(11),DATEPART(year,Sage))='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 C#,Avg(score)from SC groupby C#order by Avg(score),C# 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 Sname,SC.S# ,avg(score)
from Student,SC
where Student.S#=SC.S#groupby SC.S#,Snamehaving 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 Sname,isnull(score,0)
from Student,SC,Course
where SC.S#=Student.S#and SC.C#=Course.C#and Course.Cname='数据库'and score <60;
35、查询所有学生的选课情况；
SELECT SC.S#,SC.C#,Sname,Cname
FROM SC,Student,Course
where SC.S#=Student.S#and SC.C#=Course.C#;
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 distinctstudent.S#,student.Sname,SC.C#,SC.score
FROM student,Sc
WHERE SC.score>=70AND SC.S#=student.S#;
37、查询不及格的课程，并按课程号从大到小排列
select c# from scwhere scor e <60order by C# ;
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 SC.S#,Student.Sname from SC,Student whereSC.S#=Student.S#and Score>80and C#='003';
39、求选了课程的学生人数
select count(*)from sc;
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 Student.Sname,score
from Student,SC,Course C,Teacher
where Student.S#=SC.S#andSC.C#=C.C# and
C.T#=Teacher.T#and Teacher.Tname='叶平'andSC.score=(selectmax(score)from SCwhereC#=C.C# );
41、查询各个课程及相应的选修人数
select count(*)from sc group by C#;
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.S#,B.scorefrom SC A ,SC B where A.Score=B.Scoreand A.C# <>B.C# ;
43、查询每门功成绩最好的前两名
SELECT t1.S# as 学生ID,t1.C#as 课程ID,Scoreas 分数
FROM SC t1
WHERE score IN (SELECTTOP 2score
FROMSC
WHEREt1.C#= C#
ORDERBY scoreDESC
)
ORDER BY t1.C#;
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 C# as 课程号,count(*)as 人数
from sc
group by C#
order by count(*) desc,c#
45、检索至少选修两门课程的学生学号
select S#
from sc
group by s#
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 C#,Cname
from Course
where C# in (select c# from sc group by c#)
47、查询没学过“叶平”老师讲授的任一门课程的学生姓名
select Sname from StudentwhereS# not in (select S# from Course,Teacher,SCwhere Course.T#=Teacher.T#and SC.C#=course.C#and Tname='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 S#,avg(isnull(score,0))fromSC where S# in (select S# from SCwhere
score <60group by S# having count(*)>2)groupby S#;
49、检索“004”课程分数小于60，按分数降序排列的同学学号
select S# from SCwhere C#='004'and score<60order by score desc;
50、删除“002”同学的“001”课程的成绩
delete from Sc where S#='001'and C#='001';
