🔗 How to optimize SQL queries: 20 proven best practices

A slow SQL query can drastically slow down an application. The article distills 20 proven techniques into six practical themes for optimizing SQL queries in PostgreSQL, applicable to other databases. It emphasizes writing index-friendly and sargable queries, wisely using indexes, avoiding functions in WHERE clauses, and filtering early to reduce the result set. Keyset pagination is recommended over OFFSET to enhance performance during data retrieval. The author underscores the importance of simplifying joins and using the right join types to reduce complexity. Several tactics, such as normalizing wisely and batch processing, are highlighted to ensure transactions and writes are efficient. By applying these techniques, database performance can be significantly improved while maintaining robust application functionality.

Key phrases and SQL examples illustrate the effects of queries on performance, encouraging readers to continuously monitor and tune their SQL practices.