SQL Optimizer

Systematic SQL performance analysis: parse query structure, interpret EXPLAIN plans, detect anti-patterns (N+1, full scans, cartesian joins), recommend indexes, and rewrite queries — with explanations of WHY each change improves performance, not just WHAT changed.

Reference Files

File	Contents	Load When
`references/anti-patterns.md`	Common SQL anti-patterns with detection rules and fixes	Always
`references/index-strategies.md`	Index type selection, composite index ordering, covering indexes	Index recommendations needed
`references/explain-guide.md`	Reading EXPLAIN output for PostgreSQL, MySQL, SQLite	EXPLAIN plan provided
`references/join-optimization.md`	Join type selection, join order optimization, subquery-to-join conversion	Query contains joins or subqueries

sql-optimizer

SQL Optimizer

Reference Files

Prerequisites