If you have SQL, this is possible in a few steps as long as you have fields you can use to determine what is a duplicate. These fields would be the fields you want to be unique in your file.

Assuming your file is named MyFile, start by creating a grouping view that includes just the key fields and a field for COUNT(*); use a HAVING clause such as HAVING COUNT(*) > 1. Name the view MyFileGV. This view now shows every set of keys that are duplicated (or triplicated or more).

Next, create an inner join view over MyFile and MyFileGV. Include the key fields from MyFile and a field for RRN(MyFile). Name the new field RRNfld. Since the original table is joined to the table of duplicate keys, you now have a view that shows all the record numbers for each duplicate. Name this view MyFileJV.

Next, create a grouping view over MyFileJV that includes the key fields and a field for MAX(RRNfld). This view will provide you with the highest RRN() for any of the duplicates.

So far, all you've done is create three new views. The last view tells you exactly which record numbers to delete. A DELETE statement with a WHERE clause can then be based on this last view to delete specific record numbers. The first time you run through the DELETE, the highest record numbers for each duplicate will be deleted and the temporary views will all readjust automatically. The second time you run through it, records that were originally triplicated will be deleted. And so forth for higher multiples.

When there are no more records to delete, the temporary views will be empty.

Tom Liotta

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