Using group by and having clause

Question

Using the following schema:

Supplier (sid, name, status, city)
Part (pid, name, color, weight, city)
Project (jid, name, city)
Supplies (sid, pid, jid**, qua         


        

Answer 1

1.Get supplier numbers and names for suppliers of parts supplied to at least two different projects.

 SELECT S.SID, S.NAME
 FROM SUPPLIES SP
 JOIN SUPPLIER S
 ON SP.SID = S.SID
 WHERE PID IN
 (SELECT PID FROM SUPPPLIES GROUP BY PID, JID HAVING COUNT(*) >= 2)

I am not slear about your second question