Excel + SQL availability controls
A workbook can show fleet totals, quotes, bookings and on-hire units without becoming a second production database. The safe handoff is a read-only query contract, a dated snapshot and explicit reconciliation back to source.
Control equation: available now = fleet total − booked now − on-hire now. Quote headroom also subtracts quoted units. Every product total should reconcile between SQL output and the workbook at the same reference date.
State the database type, timezone, snapshot time and permitted source view before building formulas. A workbook refreshed at one moment cannot be reconciled to a database queried at another without recording both timestamps.
Define which source values mean quoted, booked, on hire, cancelled or unavailable. Quotes may consume sales headroom without reducing physical availability; cancelled rows should consume neither.
The SQL snapshot and the daily Excel view must use the same start/end-date overlap rule. This proof treats both dates as inclusive, then applies that rule identically at the reference date and across the 14-day window.
Unknown products, malformed dates and nonpositive quantities belong in a separate exception queue with stable reason codes. They must not silently become zero, today or an invented product.
Use a least-privilege read-only view or an authorized sanitized export. The workbook receives query outputs and refresh instructions, never embedded production passwords, write access or private customer records in a public proof.
Inspect before connecting
The downloadable ZIP contains a fictional SQLite source, SQL, CSV controls, a formula-driven workbook and a machine receipt. It is proof of method only, not a live database connection, customer project or prior-client result.
Download the synthetic proof ZIP · Open the machine receipt · View the Excel service boundary