What is the Query?

[mzahid]

I have 3 tables student(s_id,s_ name),course(c_ id,c_name) and student_course( s_id(FK),c_id(F K)).
I would Like to select those students Name who have enrolled more then and equal to 3 courses.
What is the Query?

[debasisdas]

That seems to be a home work / assignment.

Kindly post the code that you have tried / working on.

[nbiswas]

Answer to What is the query?

Try this

First let's create some sample data

declare @student table(sid int, sname varchar(50))
declare @course table(cid int, cname varchar(50))
declare @student_course table(sid int, cid int)

insert into @student 
	select 1,'student1' union all select 2,'student2' union all
	select 3,'student3' union all select 4,'student4' union all
	select 5,'student5' union all select 6,'student6'
insert into @course 
	select 101,'course1' union all select 202, 'course2' union all
	select 303,'course3' union all select 404, 'course4' union all
	select 505,'course5' union all select 606, 'course6' 
insert into @student_course
	select 1,101 union all select 1,202 union all select 1,303 union all
	select 1,404 union all select 1,505 union all select 1,606 union all
	select 2,101 union all select 2,505 union all select 2,606 union all
	select 3,303 union all select 3,202 union all select 4,303 union all
	select 4,404 union all select 4,202 union all select 5,101 union all 
	select 6,101 union all select 6,202

Query 1:

select s.sid,s.sname from @student s
inner join
(	
select sid,COUNT(cid) Courses from @student_course 
group by sid
having (COUNT(cid)>=3))X
on X.sid = s.sid

Query 2:

select sid,sname from @student where sid in(
select sid from @student_course 
group by sid
having (COUNT(cid)>=3))

The output(in both the cases)

sid	sname
1	student1
2	student2
4	student4

Hope this helps

[mzahid]

What is the Query?

Thank you very much sir.....