set nocount on

create table #Agreemnts (
Agr_id int,
AgrNum int,
Cust_id int,
Vendor_id int,
Sourse_id int
)
go
create table #customers (
Cust_id int,
CustName char,
CustRegNum int
)
go
insert into #customers (Cust_id, CustName, CustRegNum) values (1, 'A', 1)
insert into #customers (Cust_id, CustName, CustRegNum) values (2, 'B', 2)
insert into #customers (Cust_id, CustName, CustRegNum) values (3, 'C', 3)
insert into #Agreemnts (Agr_id, AgrNum, Cust_id, Vendor_id, Sourse_id) values (1, 1, 1, 2, 3)

select a.Agr_id, a.AgrNum, c.CustName, c.CustRegNum, v.CustName, v.CustRegNum, s.CustName, s.CustRegNum
from
((#Agreemnts a
inner join
#customers c
on a.Cust_id = c.Cust_id)
inner join
#customers v
on a.Vendor_id = v.Cust_id)
inner join
#customers s
on a.Sourse_id = s.Cust_id


drop table #Agreemnts
drop table #customers

set nocount off