sql-assistant_skill

Overview

This skill is a comprehensive SQL query assistant that helps write, debug, optimize, and explain SQL for MySQL, PostgreSQL, SQLite, and other dialects. It supports query construction, performance tuning, schema design, and step‑by‑step explanations aimed at practical, production-ready results. Use it when you need clear, actionable SQL solutions backed by best practices.

How this skill works

The assistant inspects SQL queries, error messages, and database schemas to identify syntax issues, logic bugs, or performance bottlenecks. It suggests corrected queries, index recommendations, and query rewrites, and it explains each change in plain English. When needed it requests the database dialect and schema details to produce dialect‑accurate SQL and execution plan guidance.

When to use it

• Writing new SELECT/INSERT/UPDATE/DELETE queries for reporting or apps
• Debugging SQL errors or unexpected results
• Optimizing slow queries and recommending indexes
• Explaining complex queries, joins, window functions, or CTEs
• Designing or normalizing database schemas for performance and integrity

Best practices

• Always confirm the target SQL dialect before producing final syntax
• Provide reproducible examples or sample schema to get precise fixes
• Prefer selecting only required columns instead of SELECT *
• Use parameterized queries to avoid SQL injection
• Recommend indexes on frequently filtered/joined columns and check EXPLAIN plans

Example use cases

• Convert a correlated subquery to an indexed JOIN to improve performance
• Fix a syntax error and explain why the original failed (e.g., unquoted literals)
• Design a normalized user/orders schema with primary/foreign keys and indexes
• Explain a multi-join aggregate query step‑by‑step for analytics teams
• Rewrite pagination and ranking queries for large datasets using window functions