SQL performance tuning is the process of improving how a database works by making queries run faster and using system resources more efficiently. It helps speed up data retrieval, reduce slowdowns, and ensure applications run smoothly. Common tuning techniques include optimizing queries, creating better indexes, and adjusting database settings. Whether using MySQL, SQL Server, PostgreSQL, or Oracle, proper tuning helps businesses handle more data, reduce wait times, and improve overall performance. A well-tuned database means fewer crashes, faster reports, and a better experience for users.