SQL statement exercises

sql Sentence exercises

Have a look , You'll see ！

1、 Inquire about students' course selection , The student number is required to be displayed 、 full name 、 Course no. 
SELECT a.sno,a.sname,b.cno from dbo.student as a
right join dbo.sc as b on a.sno= b.sno


2、 Inquire about ‘ Law school, ’ Students' courses , Ask to list the students' names 、 The course number and grade of the course taken .
select a.sname,b.cno,b.grade from dbo.student as a
inner join dbo.sc as b on a.sno = b.sno
where sdept=' Law school, '


3、 Inquire about '' School of computer science '' Optional ‘ Database and application ’ Students' grades of the course , Ask to list the student's name 、 Course name and grade .
select a.sname,c.cname,b.grade from dbo.student as a
inner join dbo.sc as b on a.sno = b.sno
inner join dbo.course as c on b.cno= c.cno 
where a.sdept=' School of computer science ' and c.cname=' Database and application '


4、 Query all repaired ‘ Military theory ’ What the students do in the course , Students' names and departments are required to be listed .( Multi table connection )
select a.sname,a.sdept from dbo.student as a
inner join dbo.sc as b on a.sno = b.sno
inner join dbo.course as c on b.cno= c.cno 
where c.cname=' Military theory '


5、 Inquire about the students' courses , Including students who have taken courses and students who have not taken courses , The student number is required to be displayed 、 full name 、 Course no. .
select a.sno,a.sname,b.cno from dbo.student as a
left join dbo.sc as b on a.sno = b.sno
left join dbo.course as c on b.cno= c.cno 


6、 Check which students did not choose a course , The student number is required 、 Name and department .
select a.sno,a.sname,a.sdept from dbo.student as a
left join dbo.sc as b on a.sno = b.sno
left join dbo.course as c on b.cno= c.cno 
where c.cname is null


7、 Use subquery to query and ‘ Monkey D Luffy ’ Student number of students in the same department 、 full name 、 departments .
select * from dbo.student as a
where a.sname !=' Monkey D Luffy ' and a.sdept in(select b.sdept  from dbo.student as b where b.sname =' Monkey D Luffy ')


8、 Use the subquery to find out that the average score is greater than 80 The student number of the student 、 full name 、 departments .
select s.sno,s.sname,s.sdept from dbo.student  as s
where s.sno in (select b.sno from dbo.sc as b group by b.sno having avg(b.grade)>80 )


9、 The subquery is used to repair ‘A008’ All data of students whose grades are higher than the average of this course .
select * from dbo.student as s
inner join dbo.sc as t on s.sno = t.sno  
inner join dbo.course as c on t.cno=c.cno
where t.cno='A008'
and t.grade>(select avg(v.grade) from dbo.course as t 
inner join dbo.sc as v on t.cno=v.cno
where t.cno='A008')


10、 Inquire about ‘’ Medical school ‘’ The student number of the student with the highest test scores .
 Law 1 ：
select top 1 a.sno,max(grade) from dbo.student as a
inner join dbo.sc as b on a.sno = b.sno
where a.sdept=' Medical school ' 
group by a.sno
order by max(grade)desc

 Law two ：
select top 1 st.sno
from student st left join sc s on st.sno=s.sno where st.sdept=' Medical school '
order by s.grade desc