Minimum from muliple tables

[inhops]

I have a query that is working, but I am looking to make it faster. We import 13 csv files daily into 13 Access tables. The files have an ItemID and price. We need to get the minimum of the raw data across the 13 tables & then manipulate the prices some (in the query) and get the lowest of the manipulated prices again for the 13 tables for each ItemID - some might be blank. We are using a MinOfList function in the query to get the minimum of the 13 numbers. But this is very time consuming since we have to run the Min function twice (with 13 input parameters) for each ItemID - about 15,000 records. It takes about 1 minute to run the query. Any thoughts on how we can streamline this? Thanks for your help.

[orange]

Why do you have 13 tables? Could you please tell us more about the application, the csv's, and the tables. It sounds like there may be more to the story than what you have told us.

[inhops]

The CSV files are exported/created from another program which parses data from 13 different websites - SKU and current price. We then import these 13 files into Access to find the "best" price - some of the prices will be "thrown out" i.e. not used. Then we need to determine the lowest of the good/remaining prices.