I need to get an invoice total. The invoice line items are in 3 files, each of which may have any number of records for a given invoice. The Tables are Labor, Parts, and Fees. The fields I need to total are Labor.LSum, Parts.PSum, Parts.PTax and Fees.FSum.

Is it possible to get a single sum with a SQL Select or even an accurate sum of each of the four fields in one record?

If there are 2 records in each table for a given invoice, everything I try returns 6 times one of the records for each field being summed.