# SQL patterns I use to catch transaction fraud

**URL:** <https://forum.kirupa.com/t/sql-patterns-i-use-to-catch-transaction-fraud/681537>\
**Category:** tech news\
**Created:** [May 16, 2026, 4:19am UTC](https://forum.kirupa.com/t/sql-patterns-i-use-to-catch-transaction-fraud/681537 "2026-05-16T04:19:25Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![WaffleFries](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/wafflefries/32/31185_2.png) [@WaffleFries](https://forum.kirupa.com/u/WaffleFries)\
**Post date:** [May 16, 2026, 4:19am UTC](https://forum.kirupa.com/t/sql-patterns-i-use-to-catch-transaction-fraud/681537/1 "2026-05-16T04:19:25Z")

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Article URL: [Six SQL patterns I use to catch transaction fraud](https://analytics.fixelsmith.com/posts/sql-fraud-patterns/) Comments URL: [https://news.ycombinator.com/item.id=48155212](https://news.ycombinator.com/item.id=48155212) Points: 24 # Comments: 0.

> **[Six SQL patterns I use to catch transaction fraud](https://analytics.fixelsmith.com/posts/sql-fraud-patterns/)**
>
> 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.

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**Author:** ![Quelly](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/quelly/32/31386_2.png) [@Quelly](https://forum.kirupa.com/u/Quelly)\
**Post date:** [May 17, 2026, 4:40am UTC](https://forum.kirupa.com/t/sql-patterns-i-use-to-catch-transaction-fraud/681537/2 "2026-05-17T04:40:26Z")

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This is the kind of stuff I wish more “fraud detection” posts showed — actual queries, not just vibes. Even outside fraud, those window-function velocity patterns are basically the SQL version of spotting feedback loops in a signal chain: you’re not looking at one event, you’re looking at the timing between events.