Master SQL query optimization, indexing strategies, and EXPLAIN analysis to eliminate slow queries.

• Covers EXPLAIN plan analysis with key metrics (Seq Scan, Index Scan, cost, rows, execution time) and five index types (B-Tree, Hash, GIN, GiST, BRIN) for different query patterns
• Includes five core optimization patterns: eliminating N+1 queries, cursor-based pagination, efficient aggregation, subquery transformation, and batch operations
• Provides advanced techniques like materialized views, table partitioning, and query hints for large-scale performance tuning
• Includes monitoring queries to identify slow queries, missing indexes, and unused indexes in PostgreSQL