SQL Query Optimization Toolkit

Complete SQL performance toolkit for agents and developers. Covers EXPLAIN plan interpretation (with lookup tables for PostgreSQL and MySQL), index strategy and column ordering rules, 8 common antipatterns with fixes (N+1, SELECT *, OFFSET pagination, function-on-indexed-column, correlated subqueries, implicit casting, OR conditions, missing LIMIT), query rewriting patterns (subquery to JOIN, CTE materialization, batch operations), slow query diagnostics, and a step-by-step optimization checklist. Works with any database accessible via CLI — no external dependencies or API keys required. 12KB of battle-tested SQL knowledge distilled into copy-pasteable commands.