By the way, you can try to save the current totals to another table. update it through triggers when the inventory transactions changed. it may lead to better performance on a large set of inventory transactions for query current totals
If you are going to do this, my recommendation is to store periodic summaries (i.e. for sum through date) and then aggregate rolling forward. This vastly simplifies querying and data validation if you are only appending data.
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Best Wishes,
Chris Travers
Efficito: Hosted Accounting and ERP. Robust and Flexible. No vendor lock-in.