Joining Tables

Hi,
I have a table with fields as partnerid, contractno.
The partnerid field has the Id number which can be a supplier or a customer.
I need to get the partner id(supplier) and the partner id (customers) of that particular supplier only. I tried with self join but the data is data is replicating.

Data in table
PId ContractNo
20045 1567
435 1567
123 1567
345 1678
1004 1678

I need to display the data in the following format.

PId(Supplier) PId(Customer)
20045 1567
20045 435
20045 123
345 1678
345 1004

But I'm getting the data replicated with all records joined every record.
Give the suggestion.Your data doesn't make sense in any way that would give you the query you want? How do you know which PId is a supplier or Customer? Without some kind of a key to indicate that, there's nothing you can do about your issue.|||Hai Madhavi,
Can you show us the query that you have written?

Madhivanan