The tables used to create the query in question are as follows:
"tblmarkets" - field used is "market code".
"tblexistingcustomers" - field used is "e customer account ref."
"tblpotentialcustomers" - field used is "p customer account ref.".

Both "tblexistingcustomers" and "tblpotentialcustomers" are linked togehter by having a "market code" assigned to each record.

In the query I am trying to display potential customers together with existing customers sorted by market sector. When I come to run this report however, I find that because there are more records in "tblexistingcustomers" than "tblpotentialcustomers", the query displays the same potential customer more than once. Is there any way of getting the query to display a company just once for the market sector that it comes under?

have you not asked this question once in reports where I answered you???