sql - Using distinct keyword with join -

my professor has given me assignment.

write query produce snum values of salespeople (suppress duplicates) orders in orders table.

salespeople

snum number(4)
sname varchar2(10)
city varchar2(10)
comm number(3,2)

customer

cnum number(4)
cname varchar2(10)
city varchar2(10)
rating number(4)
snum number(4)

orders

onum number(4)
amt number(7,2)
odate date
cnum number(4)
snum number(4)

i not sure if have understood question completely.

i have written query using join.

select distinct s.snum,onum salespeople s, ordrs o s.snum = o.snum order snum; 

and output is

      snum       onum ---------- ----------       1001       3003       1001       3008       1001       3011       1002       3005       1002       3007       1002       3010       1004       3002       1007       3001       1007       3006 

but don't want snum repeated. can point me in right direction ?

thanks.

the question asks "write query produce snum values of salespeople (suppress duplicates) orders in orders table" - doesn't specify need include order numbers. (it implies don't need order numbers, since including them duplicate snum values.)

given snum appears on orders table, should relatively simple select distinct list of snum values orders table.