经典SQL查询语句50条

create table student (

sid varchar(50) primary key ,

sname varchar(20) ,

sage int ,

ssex varchar(5)

)

create table teacher (

tid varchar(50) primary key ,

tname varchar(20)

)

create table course(

cid varchar(50) primary key ,

cname varchar(30),

tid varchar(50) ,

)

alter table course add constraint fk_1 foreign key (tid) references teacher(tid); create table sc(

sid varchar(50) not null,

cid varchar(50) not null,

score int not null

)

alter table sc add constraint fk_2 foreign key (sid) references student(sid); alter table sc add constraint fk_3 foreign key (cid) references course(cid);

insert into teacher (tid,tname) values ('001','teacher1')

insert into teacher (tid,tname) values ('002','teacher2')

insert into teacher (tid,tname) values ('003','teacher3')

insert into teacher (tid,tname) values ('004','teacher4')

insert into teacher (tid,tname) values ('005','teacher5')

insert into student values ('001','student1',20,'man')

insert into student values ('002','student2',16,'woman')

insert into student values ('003','student3',30,'man')

insert into student values ('004','student4',9,'woman')

insert into student values ('005','student5',25,'man')

insert into course values ('001','course1','001')

insert into course values ('002','course2','002')

insert into course values ('003','course3','003')

insert into course values ('004','course4','004')

insert into course values ('005','course5','005')

insert into sc values ('001','001','80')

insert into sc values ('001','002','60')

insert into sc values ('001','003','40')

insert into sc values ('001','004','100')

insert into sc values ('001','005','90')

insert into sc values ('002','001','40')

insert into sc values ('002','002','60')

insert into sc values ('002','003','70')

insert into sc values ('002','004','100')

insert into sc values ('002','005','90')

insert into sc values ('003','001','90')

insert into sc values ('003','002','60')

insert into sc values ('003','003','70')

insert into sc values ('003','004','60')

insert into sc values ('003','005','40')

--1、查询“001”课程比“002”课程成绩高的所有学生的学号；

select a.sid from

(select sid ,score from sc where cid='001') a,

(select sid,score from sc where cid='002') b

where a.score>b.score and a.sid=b.sid

--2、查询平均成绩大于60分的同学的学号和平均成绩；

select sid ,avg(score) from sc group by sid having avg(score)>60

--3、查询所有同学的学号、姓名、选课数、总成绩

1)select a.sid ,a.sname ,(select count(*) from sc as b where a.sid=b.sid) '选课数',(select sum(score) from sc as b where a.sid=b.sid) '总成绩' from student as a

2)select a.sid ,a.sname , count(b.cid) '选课数',sum(b.score) '总成绩' from student a left outer join sc b on a.sid=b.sid group by a.sid,a.sname

--4、查询姓“李”的老师的个数

select count(*) from teacher where tname like '李%'

--5、查询没学过“teacher1”老师课的同学的学号、姓名

select sid ,sname from student where sid not in

(select sid from teacher t,course c,sc s where s.cid=c.cid and t.tid=c.tid and t.tname='teacher1')

--6、查询学过“001”并且也学过编号“002”课程的同学的学号、姓名；

--解法1.

select sid ,sname from student where sid in

(select sid from sc where cid='001') and sid in (select sid from sc where cid='002')

--解法2.

select s.sid ,s.sname from student s,sc where s.sid=sc.sid and cid='001' and exists(

select * from sc sc1 where sc1.sid=sc.sid and sc1.cid='002')

--7、查询学过“teacher1”老师所教的所有课的同学的学号、姓名；

select sid,sname from student where sid in(select sc.sid from sc,course c,teacher t where t.tname='teacher1' and t.tid=c.tid

and c.cid = sc.cid group by sid having count(sid)=(select count(cid) from course c,teacher t

where t.tname='teacher1' and t.tid=c.tid ))

--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 sid,sname from(select s.sid ,sname ,score score1,

(select score from sc where sc.sid=s.sid and sc.cid='002')score2

from student s,sc where s.sid=sc.sid and sc.cid='001') a where a.score1>a.score2

--9、查询所有课程成绩小于60分的同学的学号、姓名；

select sid ,sname from student where sid not in(select distinct(sid) from sc where score>60)

--10、查询没有学全所有课的同学的学号、姓名(包括一门课程都没学的同学）；

select s.sid ,sname from student s left outer join sc on sc.sid=s.sid group by s.sid ,sname

having count(cid)<(select count(cid) from course)

--11、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

select distinct(s.sid),sname from student s,sc where s.sid=sc.sid and sc.cid in(select cid from sc where sc.sid='001' )

--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；

--个人认为同11题

--13、把“SC”表中“teacher1”老师教的课的成绩都更改为此课程的平均成绩；

update sc set score=(select avg(score) from sc s1 where sc.cid=s1.cid)

from course c,teacher t ,sc where sc.cid=c.cid and c.tid=t.tid and t.tname='teacher1'

--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；

select s.sid,sname from sc ,student s where sc.sid=s.sid and sc.cid in

(select cid from sc where sid='002') group by s.sid,sname having count(*)=

(select count(cid) from sc where sid='002')

--15、删除学习“teacher7”老师课的SC表记录；

delete sc from teacher t,course c where t.tid=c.cid and t.tname='teacher7' and sc.cid=c.cid

--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“003”课--程的同学学号 2、成绩为'002'号课的平均成绩；

Insert SC select Sid,'002',(Select avg(score)

from SC where Cid='002') from Student where Sid not in (Select Sid from SC where Cid='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 sid '学生ID',(select score from sc s where s.sid=sc.sid and s.cid='001') '数据库',

(select score from sc s where s.sid=sc.sid and s.cid='002') '企业管理',

(select score from sc s where s.sid=sc.sid and s.cid='003') '英语',

count(cid) '有效课程数',avg(score) '有效平均分'

from sc group by sid order by '有效平均分'

--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 cid '课程ID',max(score) '最高分',min(score) '最低分' from sc group by cid

--19、查询各科课号，课名，该科平均成绩和及格率的百分数并按及格率从高到低排序

select sc.cid,cname,avg(score) '平均分',100*sum(case when isnull(score,0)>=60 then 1 else 0 end)/count(*) '及格率'

from sc,course c where sc.cid=c.cid group by sc.cid ,cname order by '及格率' 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 cid='001' then score else 0 end)/sum(case when cid='001' then 1 else 0 end) '企业管理平均分',

100*sum(case when cid='001' and isnull(score,0)>=60 then 1 else 0 end)/sum(case when cid='001' then 1 else 0 end) '企业管理及格率',

sum(case when cid='002' then score else 0 end)/sum(case when cid='002' then 1 else 0 end) '马克思平均分',

100*sum(case when cid='002' and isnull(score,0)>=60 then 1 else 0 end)/sum(case when cid='002' then 1 else 0 end) '马克思及格率',

sum(case when cid='003' then score else 0 end)/sum(case when cid='003' then 1 else 0 end) 'OO&UML平均分',

100*sum(case when cid='003' and isnull(score,0)>=60 then 1 else 0 end)/sum(case when cid='003' then 1 else 0 end) 'OO&UML及格率',

sum(case when cid='004' then score else 0 end)/sum(case when cid='004' then 1 else 0 end) '数据库平均分

',

100*sum(case when cid='004' and isnull(score,0)>=60 then 1 else 0 end)/sum(case when cid='004' then 1 else 0 end) '数据库及格率'

from sc

--21、查询不同老师所教不同课程平均分从高到低显示(注：一门课程只能有一位老师教)

select c.cid,tid, avg(score) '平均分' from sc,course c where sc.cid=c.cid group by c.cid,tid order by '

平均分'

--22、查询如下课程成绩第 3 名到第 5 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,总分

select distinct top 3 with ties sc.sid ,s.sname,s1.score '企业管理',s2.score '马克思',s3.score

'UML',s4.score '数据库',

isnull(s1.score,0)+isnull(s2.score,0)+isnull(s3.score,0)+isnull(s4.score,0) as '总分'

from student s,sc left join sc s1 on sc.sid=s1.sid and s1.cid='001'

left join sc s2 on sc.sid=s2.sid and s2.cid='002'

left join sc s3 on sc.sid=s3.sid and s3.cid='003'

left join sc s4 on sc.sid=s4.sid and s4.cid='004'

where s.sid=sc.sid

and isnull(s1.score,0)+isnull(s2.score,0)+isnull(s3.score,0)+isnull(s4.score,0) not in (

select distinct top 3 with ties isnull(s1.score,0)+isnull(s2.score,0)+isnull(s3.score,0)+isnull(s4.scor e,0) '总分'

from sc left join sc s1 on sc.sid=s1.sid and s1.cid='001'

left join sc s2 on sc.sid=s2.sid and s2.cid='002'

left join sc s3 on sc.sid=s3.sid and s3.cid='003'

left join sc s4 on sc.sid=s4.sid and s4.cid='004'

order by '总分' desc

) order by '总分' 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.cid '课程ID',cname '课程名称' ,sum(case when isnull(score,0)>=85 then 1 else 0 end) '[100-85]', sum(case when isnull(score,0)>=70 and isnull(score,0)<85 then 1 else 0 end) '[85-70]',

sum(case when isnull(score,0)>=60 and isnull(score,0)<70 then 1 else 0 end) '[70-60]',

sum(case when isnull(score,0)<60 then 1 else 0 end) '[<60]'

from sc,course c where sc.cid=c.cid group by sc.cid ,cname

--24、查询学生平均成绩及其名次

select 1+(select count(*) from

(select sid,avg(score) '平均成绩' from sc group by sid )t1 where t1.平均成绩>t2.平均成绩) 名次,

sid,平均成绩

from

(select sid,avg(score) '平均成绩' from sc group by sid) t2 order by '名次'

--25、查询各科成绩前三名的记录:(不考虑成绩并列情况)

select sid,cid,score from sc s where score in(select top 3 score from sc where s.cid=sc.cid order by score desc)

order by cid

--26、查询每门课程被选修的学生数

select cid,count(sid) from sc group by cid

--27、查询出只选修了一门课程的全部学生的学号和姓名

select s.sid ,sname from sc,student s where sc.sid=s.sid group by s.sid,sname having count(sc.ci d)=1

--28、查询男生、女生人数

select count(sid) '女生人数', (select count(sid) from student where ssex='man' group by ssex) '男生人数' from student where ssex='woman' group by ssex;

--29、查询姓“张”的学生名单

select * from student where sname like '张%'

--30、查询同名同性学生名单，并统计同名人数

select sname,count(*) '同名人数' from student group by sname having count(sname)>1

--31、1981年出生的学生名单(注：Student表中Sage列的类型是datetime)

select * 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 cid, avg(score) from sc group by cid order by avg(score) asc ,cid 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 s.sid ,sname ,avg(score) from student s,sc where s.sid=sc.sid group by s.sid,sname having

avg(score)>85

--34、查询课程名称为course1，且分数低于60的学生姓名和分数

select s.sid,sname,cname,score from course c,sc,student s

where c.cid=sc.cid and sc.sid=s.sid and isnull(score,0)<60 and cname='course1'

--35、查询所有学生的选课情况；

select s.sid,sname,cid from sc,student s where sc.sid=s.sid

--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 sname,cname,score from student s,course c,sc where s.sid=sc.sid and c.cid=sc.cid and score>70

--37、查询不及格的课程，并按课程号从大到小排列

select * from sc where isnull(score,0)<60 order by cid desc

--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 s.sid,sname from sc ,student s where sc.sid=s.sid and cid='003' and isnull(score,0)>80

--39、求选了课程的学生人数

select count(cid) from course

--40、查询选修“teacher1”老师所授课程的学生中，成绩最高的学生姓名及其成绩

select sname,score from student s,sc,teacher t,course c

where s.sid=sc.sid and sc.cid=c.cid and c.tid=t.tid and t.tname='teacher1'

and score=(select max(s1.score) from sc s1 where sc.cid=s1.cid)

--41、查询各个课程及相应的选修人数

select cid ,count(sid) from sc group by cid

--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 sc1.sid ,sc1.cid,sc1.score from sc sc1,sc sc2 where sc1.score=sc2.score and sc1.cid<>sc2.cid

--43、查询每门功成绩最好的前两名

select * from sc s1 where s1.score in (select top 2 score from sc s2 where s1.cid=s2.cid )

--44、统计每门课程的学生选修人数（超过2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 cid,count(*) '选修人数' from sc group by cid having count(*) >2 order by '选修人数' desc ,cid

--45、检索至少选修两门课程的学生学号

select sid ,count(*) from sc group by sid 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 sc.cid,cname from sc ,course c where sc.cid=c.cid group by sc.cid,cname having count(cname)= (select count(*) from student )

--47、查询没学过“teacher1”老师讲授的任一门课程的学生姓名

select sname from sc,student s where

sc.sid=s.sid and sc.sid not in( select distinct sid from sc where cid=sc.cid and cid='001')

--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 sid ,avg(score) from sc where

sid in (select sid from sc where isnull(score,0)<60 group by sid having count(*)>2 ) group by sid

--49、检索“004”课程分数小于60，按分数降序排列的同学学号

select sid from sc where cid='004' order by sid desc

--50、删除“002”同学的“001”课程的成绩

delete sc where sid='002' and cid='001'

一些常用的正则表达式

"^\d+$" //非负整数（正整数 + 0）

"^[0-9]*[1-9][0-9]*$" //正整数

"^((-\d+)|(0+))$" //非正整数（负整数 + 0）

"^-[0-9]*[1-9][0-9]*$" //负整数

"^-?\d+$" //整数

"^\d+(\.\d+)?$" //非负浮点数（正浮点数 + 0）

"^(([0-9]+\.[0-9]*[1-9][0-9]*)|([0-9]*[1-9][0-9]*\.[0-9]+)|([0-9]*[1-9][0-9]*))$" //正浮点数

"^((-\d+(\.\d+)?)|(0+(\.0+)?))$" //非正浮点数（负浮点数 + 0）

"^(-(([0-9]+\.[0-9]*[1-9][0-9]*)|([0-9]*[1-9][0-9]*\.[0-9]+)|([0-9]*[1-9][0-9]*)))$" //负浮点数

"^(-?\d+)(\.\d+)?$" //浮点数

"^[A-Za-z]+$" //由26个英文字母组成的字符串

"^[A-Z]+$" //由26个英文字母的大写组成的字符串

"^[a-z]+$" //由26个英文字母的小写组成的字符串

"^[A-Za-z0-9]+$" //由数字和26个英文字母组成的字符串

"^\w+$" //由数字、26个英文字母或者下划线组成的字符串

"^[\w-]+(\.[\w-]+)*@[\w-]+(\.[\w-]+)+$" //email地址

"^[a-zA-z]+://(\w+(-\w+)*)(\.(\w+(-\w+)*))*(\?\S*)?$" //url

"/^[+]{0,1}(\d){1,3}[ ]?([-]?((\d)|[ ]){1,12})+$/" //校验普通电话、传真号码：可以“+”开头，除数字外，可含有“-

”