# SQL

> Database query language.

- Skill: `dhaupin/sql` (Agent Skill)
- Install (CLI): `npx skillmds@latest add dhaupin/sql`
- Raw SKILL.md: https://api.skillmd.com/api/skills/dhaupin/sql/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Data & Analytics
- License: MIT
- Author: dhaupin (https://skillmd.com/u/dhaupin)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/dhaupin/sql

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# SQL

> Database query language.

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## When To Use

- Database queries
- Data analysis
- CRUD operations

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## What To Do

### 1. Basic

```sql
SELECT columns FROM table
WHERE condition
ORDER BY column
LIMIT n
```

### 2. Operations

| Keyword | What |
|---------|------|
| SELECT | Read |
| INSERT | Create |
| UPDATE | Update |
| DELETE | Remove |
| JOIN | Combine |

### 3. Aggregates

```sql
SELECT COUNT(*), SUM(col), AVG(col), MIN(col), MAX(col)
FROM table
GROUP BY col
HAVING count > 1
```

### 4. Subqueries

```sql
SELECT * FROM users
WHERE id IN (SELECT user_id FROM orders)
```

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**Role**: SQL Developer  
**Input**: Query  
**Output**: Results

> Query.