Claude Code Convinced Me To Simplify My SQL JOINs

A developer with 20 years of strong SQL opinions shares how Claude Code convinced him to change his JOIN structuring approach. He previously put all filtering conditions in ON clauses to mimic human top-to-bottom thinking, but Claude Code made compelling arguments for separating concerns: ON clauses should describe table relationships, while WHERE clauses handle row filtering. Key arguments included easier debugging (centralized filtering is easier to comment out incrementally), consistency across INNER and LEFT OUTER JOINs (which often require WHERE filtering anyway to avoid subtle bugs), and alignment with how most developers read SQL.