>Is each PoNum unique, or do they overlap? In other words, can customer #1 have po #1, and customer #2 have po #1? If not, then you do not need an index on CustID+PoNum. To get the invoices for a customer:
>
>SELECT * FROM PastInvoices WHERE CustID = ?lcCustID
>
>To get a specific invoice:
>
>SELECT * FROM PastInvoices WHERE PoNum = ?lcPoNum
>
>Hope that helps, rather than confuses :).

These are po numbers that customers give us...so there are no guarantees about uniqueness. As a matter of fact, we have gotten a duplicate PO number within a customer (from a major retailer...I wouldn't expect that to happen). The only time we retrieve an invoice (or open order) this way is when a store calls and says "Where is po number 12345?"