bq-query-optimization

What problem does it solve?

This skill helps analysts optimize and debug BigQuery SQL queries for performance and cost.

Core Features & Use Cases

• Parameterized queries: write safe, reusable SQL with bound parameters to improve caching and readability.
• Advanced functions: leverage UDFs, scripting, and window functions (QUALIFY, ROW_NUMBER, RANK, LEAD/LAG) to simplify complex analyses.
• BigQuery-specific patterns: apply best practices for EXCEPT/REPLACE usage, JSON/ARRAY/STRUCT handling, NOT IN with NULLs, and efficient DML.
• Use Case: optimize a nightly analytics query that scans a large dataset, replacing SELECT * with targeted columns and adding partition filters to reduce cost and improve performance.

Quick Start

Start with a simple query, enable parameterization, review the execution plan, and iteratively apply the optimization techniques described above. Then validate results against a non-optimized baseline.