Series: The Data Engineer’s Playbook | Tier 1 — Foundation | Estimated read: 18 min
Series: The Data Engineer’s Playbook | Tier 1 — Foundation | Estimated read: 18 minContinue reading on Medium » Read More Sql on Medium
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DE Playbook #3 — Visa and the NOT IN Trap: How a Single Subquery Blew Up a Fraud Detection Engine
Byali
Apr 14, 2026