This is a comprehensive SQL reference that covers database design patterns, query optimization, and cross-platform syntax for PostgreSQL, MySQL, and SQL Server. You get normalized schema examples, complex join patterns, window functions, subqueries, and indexing strategies all in one place. The skill includes actual DDL examples showing proper foreign key constraints, check constraints, and index placement. Most useful when you're architecting a new database schema or debugging slow queries, since it demonstrates both the right way to structure relationships and how to write efficient queries with CTEs and window functions. The examples are production-ready, not toy datasets, which makes it easy to adapt patterns to real applications.
npx skills add https://github.com/personamanagmentlayer/pcl --skill sql-expert