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Banner: a podium with two people tied for third place and only one of them in the report

Databases Bug Report

Top-N report silently dropped tied rows: ROW_NUMBER vs RANK vs DENSE_RANK

John Nguyen · Jun 3, 2026 · 8 min read

Our monthly 'top 3 sellers per region' bonus report left out a sales rep who tied for third, and a rerun picked the other one. ROW_NUMBER breaks ties arbitrarily. We show how to pick RANK, DENSE_RANK or WITH TIES on purpose.

Banner: a sliding window frame moving across rows of a table with a rising line chart above

Databases

SQL window functions for real reports: LAG gaps, running totals and frames

John Nguyen · Jan 13, 2025 · 9 min read

Most reporting queries that end up as nested subqueries or app-side loops are one window function away from simple. A practical tour of LAG for gaps, running totals, moving averages and the frame clause defaults that quietly give wrong numbers.