# Skylv SQL Helper

> SQL query builder and optimizer. Generates queries, explains execution plans, and optimizes slow queries. Triggers: sql query, database query, sql optimization.

- Skill: `luokai0/skylv-sql-helper` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add luokai0/skylv-sql-helper`
- Raw SKILL.md: https://api.skillmd.com/api/skills/luokai0/skylv-sql-helper/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Data & Analytics
- License: MIT
- Author: luokai0 (https://skillmd.com/u/luokai0)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/luokai0/skylv-sql-helper

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# SQL Helper

## Overview
Helps write, optimize, and debug SQL queries.

## When to Use
- User asks to "write a SQL query" or "optimize this query"
- Debugging slow database operations

## Pagination
SELECT * FROM users ORDER BY id LIMIT 20 OFFSET 40;

## Join with Aggregation
SELECT u.name, COUNT(o.id) as order_count
FROM users u
LEFT JOIN orders o ON u.id = o.user_id
GROUP BY u.id;

## Optimization Rules
- Add indexes on WHERE/JOIN columns
- Avoid SELECT * - specify columns
- Use EXPLAIN to analyze execution plan
- Optimize JOIN order (small table first)
- Add LIMIT for pagination

## Anti-Patterns to Avoid
- SELECT * in production code
- Nested subqueries (use JOINs or CTEs)
- OR in WHERE clause (use IN or UNION)