Question : Adding a unique identifier to a field for export

I am trying to create a file for import to our accounting program; I am exporting a PO, see example below. The RefNumber below is the unique identifier, so right now, the vendor shows up as Microsoft for all the lines. I need to add something to the query that changes the ref number to "12345-1" for the MS line, "12345-2" for all the Ingram lines, "12345-3" for TechData, and so on.

Payee      RefNumber      Transaction Date
Microsoft      12345      11/04/2009
Ingram Micro      12345      11/04/2009
Ingram Micro      12345      11/04/2009
Ingram Micro      12345      11/04/2009
TechData      12345      11/04/2009
TechData      12345      11/04/2009

Answer : Adding a unique identifier to a field for export

or w/o function

update mytable m1
set id = id & "-" & (select count(1)+1 from mytable m2 where m2.Payee=m1.Payee and m2.RefNumber=m1.RefNumber and m2.id< m1.id)
where instr(id,"-") = -1