SQL Query Refactoring for Improved Maintainability

Abstract

SQL query refactoring is important for improved maintainability because enterprise applications often depend on complex queries that become difficult to read, modify, debug, and reuse over time. Refactoring helps restructure SQL statements without changing their output, making database logic clearer, more efficient, and easier to manage. Existing literature highlights query simplification, removal of redundant joins, use of meaningful aliases, stored views, common table expressions, indexing alignment, and execution plan review as major practices for improving SQL maintainability. However, many organizations still face challenges such as lengthy nested queries, repeated logic, unclear naming, poor documentation, inefficient joins, and high dependency between application code and database queries. This research is important because poorly maintained SQL queries can increase development effort, introduce reporting errors, slow performance tuning, and reduce long-term system reliability. This article discusses SQL query refactoring for improved maintainability, focusing on query restructuring, modular logic design, naming consistency, join simplification, reusable SQL components, validation testing, and performance review. The study concludes that effective SQL refactoring improves readability, reduces maintenance effort, strengthens query reliability, and supports scalable enterprise database development.