SQL Expert Skill

Expert guidance for writing, optimizing, and managing SQL databases across PostgreSQL, MySQL, SQLite, and SQL Server.

Core Capabilities

This skill enables you to:

• Write complex SQL queries with JOINs, subqueries, CTEs, and window functions
• Optimize slow queries using EXPLAIN plans and index recommendations
• Design database schemas with proper normalization (1NF, 2NF, 3NF, BCNF)
• Create effective indexes for query performance
• Write database migrations safely with rollback support
• Debug SQL errors and understand error messages
• Handle transactions with proper isolation levels
• Work with JSON/JSONB data types
• Generate sample data for testing
• Convert between database dialects (PostgreSQL ↔ MySQL ↔ SQLite)