PostgreSQL 18 has arrived with some fantastic improvements, and among them, the RETURNING clause enhancements stand out as a feature that every PostgreSQL developer and DBA should be excited about. In this blog, I'll explore these enhancements, with particular focus on the MERGE RETURNING clause enhancement, and demonstrate how they can simplify your application architecture and improve data tracking capabilities.

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PostgreSQL 18 introduces enhanced RETURNING clause capabilities with OLD and NEW aliases, allowing developers to capture both before and after states of data in INSERT, UPDATE, DELETE, and MERGE operations within a single atomic statement. This eliminates the need for separate SELECT queries, complex triggers, or application-level change tracking. The feature is particularly powerful for MERGE operations, enabling sophisticated upsert patterns with complete visibility into what changed. Practical examples demonstrate building audit trails, tracking inventory changes, and comparing values without additional database round trips or trigger overhead.

PostgreSQL 18 RETURNING Enhancements: A Game Changer for Modern Applications

Background: The RETURNING Clause Evolution