help with sub queries

[FoxStudent]

I am having a problem answering the following question:
Get the average salary of those projects that have more than seven people working on them.
The following tables make up the database:
DEPT(Dno , Dname, Location, Numstaff)
WORKS(Eno* , Pno* , Role)
EMP(Eno , Ename, Salary, Supno, Dno*)
PROJ(Pno , Pname, Ptype, Budget)

Thank you,
Grainne B-)

 

[Cagliostro]

I can't really understand, what is DEPT for?

select pname, avg(b.salary) from
(
select pno, count(*) x from works group by pno having
count(*)>7
) a
inner join
(select eno, salary from EMP) b on a.eno = b.eno
inner join
PROJ on a.PNO = PROJ.pno
group by pname John Fill

http://ournet.md/~ifilipski/1c.bmp

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