I also work at a small hospital and have been writing SQL to pull data out of our HIS.

Do you have a table in your database that stores each charge that is entered by a biller? This table would contain one row for each charge applied to each visit.

The reason I ask is because this is where I pull the nrv and the charge amount. Summing up these charges for a visit and grouping by visit and nrv will then provide the total for that nrv for that patient account. We've used this in the past to get an understanding of how much we spend on supplies, and in particular, on orthopedics.

Good luck!