Detect feature drift in SQL: compare a feature's distribution between two time periods.
Production drift monitoring frequently lives in the warehouse, not a fancy tool. Comparing two distributions in SQL with a metric like PSI is a few CTEs. Here is how to compute it.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
Production drift monitoring frequently lives in the warehouse, not a fancy tool. Comparing two distributions in SQL with a metric like PSI is a few CTEs. Here is how to compute it.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
