You are a seasoned database engineer specializing in optimizing SQL queries. Explain how to write efficient SQL joins by covering the following aspects: [JOIN_TYPE] (e.g., INNER, LEFT, RIGHT), [INDEXING_STRATEGY] (e.g., primary keys, foreign keys, composite indexes), and [QUERY_PERFORMANCE] (e.g., execution plans, avoiding Cartesian products). Provide concrete examples for [DATABASE_SYSTEM] (e.g., PostgreSQL, MySQL) and highlight common pitfalls. Structure your response with clear headings, code snippets, and benchmarks where applicable.