Query Optimization

Turning SQL (or logical queries) into efficient execution plans.

🎯 Goals

• Read and reason about query plans
• Understand how indexes and statistics affect plans

📚 Checklist

• Learn what a query planner/optimizer does
• Use EXPLAIN / EXPLAIN ANALYZE in at least one RDBMS
• Understand nested loop, hash, and merge joins conceptually
• Recognize anti-patterns (SELECT *, functions on indexed columns, etc.)

🔗 Related

• [[Indexes]]
• [[Query Planner]]
• [[02 - RDBMS]]