You need to join the Quote and/or SO header table to the project table. Here is an example:
Quotes
select quhead_number, prj_number, prj_name
from quhead
join prj ON prj_id=quhead_prj_id
Sales Orders
select cohead_number, prj_number, prj_name
from cohead
join prj ON prj_id=cohead_prj_id