This page covers tools and techniques for analyzing SQL execution plans across database platforms. EXPLAIN ANALYZE is fundamental to query optimization, revealing how databases execute queries and where time is spent. Coverage includes explain.depesz.com (PostgreSQL EXPLAIN visualization), explain.dalibo.com (PostgreSQL plan visualization), MySQL Workbench Visual Explain, SQL Server Management Studio execution plans, and Oracle SQL Developer Explain Plan. Key concepts covered: sequential scans vs index scans, join algorithms (nested loop, hash, merge), sort operations, actual vs estimated rows (cardinality estimation), and buffer/cache usage. Understanding execution plans is prerequisite for effective optimization. The page provides interpretation guides for each major database platform with common anti-patterns and solutions. Page should cover: database-specific EXPLAIN syntax, visualization tool comparison, common execution plan problems (full table scans, poor cardinality estimates, sort spills), and optimization strategies based on plan analysis.