Practical SQL and data analytics
Working notes on fraud detection, public-sector data, and analytics engineering — from inside a program-integrity team. Mostly SQL, with the usual cloud data warehouses and BI tools. Occasionally Python. Always grounded in the actual queries I run.
Recent writing
- Eight window-function tricks beyond LAG and ROW_NUMBER
QUALIFY, frame specs, FILTER, gap-and-island, and the rest of the window-function patterns that turn five-line fraud rules into one-line filters.
- Six SQL patterns I use to catch transaction fraud
The actual queries I run when I'm hunting fraud in transaction data. Velocity, impossible distances, suspicious amounts, merchant clusters, off-hours buys, and window functions.