# Duckdb SQL

> Use when writing, debugging, optimizing, or checking DuckDB SQL syntax, statements, functions, data types, dialect, or query semantics.

- Skill: `wenerme/duckdb-sql` (Agent Skill, multi-file: 127 files)
- Install (CLI): `npx skillmds@latest add wenerme/duckdb-sql`
- Raw SKILL.md: https://api.skillmd.com/api/skills/wenerme/duckdb-sql/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Data & Analytics
- Author: wenerme (https://skillmd.com/u/wenerme)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/wenerme/duckdb-sql

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# DuckDB SQL Reference

This skill mirrors DuckDB current SQL documentation.

CRITICAL: Search `references/sql/` before giving DuckDB SQL syntax, function signatures, type semantics, statement options, dialect compatibility, or query-planning guidance. Do not infer function names or argument behavior from other SQL engines.

## Scope

- `references/sql/query_syntax/` - `SELECT`, joins, CTEs, windowing, `FROM`, `QUALIFY`, sampling, and related syntax.
- `references/sql/statements/` - DDL, DML, `COPY`, secrets, extension commands, transactions, and maintenance statements.
- `references/sql/functions/` - scalar, aggregate, window, utility, and table-function references.
- `references/sql/data_types/` and `references/sql/dialect/` - type behavior, identifiers, and compatibility rules.

## Search

```bash
rg -n "SELECT|JOIN|COPY|CREATE|function|aggregate|window|type|cast|PostgreSQL" references/sql
```

Official source: `https://github.com/duckdb/duckdb-web/tree/main/docs/current/sql`.