Learn how the pganalyze team used the open-source pg_query library to safely rewrite SQL queries and fix inefficient Postgres query plans—covering real examples like avoiding bad ORDER BY index usage and transforming OR clauses into ANY expressions.

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The pganalyze team demonstrates using the pg_query open-source library to programmatically rewrite SQL queries and fix inefficient Postgres query plans. The article walks through practical examples including adding expressions to ORDER BY clauses to prevent index misuse, and transforming multiple OR conditions into ANY expressions for better performance. By parsing queries into structured parse trees, modifying nodes, and regenerating valid SQL, pg_query enables safe, deterministic query transformations that would be difficult to achieve with regex or AI-based approaches.

How we used pg_query to rewrite queries to fix bad query plans

Example #1 - Add +0 to ORDER BY to avoid index misuse

Example #2 - Transform multiple OR clauses to ANY