---
name: "duckdb-inprocess-olap-query"
description: "Query local Parquet files, CSVs, and SQLite databases with lightning-fast vectorized SQL."
metadata:
  author: "DuckDB"
  version: "1.0.0"
  runtime_compatibility:
    - "codex"
    - "claude-code"
    - "cursor"
    - "windsurf"
triggers:
  - "query parquet with duckdb"
  - "run fast olap sql python"
  - "join parquet files duckdb"
permissions:
  fs_read: true
  fs_write: "workspace"
  shell_exec: false
  net_access: false
---

# DuckDB In-Process OLAP Parquet SQL Queries

Executes analytical queries using DuckDB: vectorized execution engine, direct querying of Parquet files without database imports, window functions, and seamless integration with Python and Arrow.

## When to Invoke
Invoke this skill whenever you need to:
- query parquet with duckdb
- run fast olap sql python
- join parquet files duckdb

## Execution SOP & Rules
1. Query files directly in SQL: SELECT * FROM read_parquet('data/*.parquet') WHERE amount > 1000.
2. Install and load extensions on demand: INSTALL spatial; LOAD spatial;.
3. Convert results seamlessly using con.execute(query).df() or .arrow() or .pl().
4. Use in-memory mode (duckdb.connect(':memory:')) for transient data pipelines.

## Verification Checklist
- Run local linting, syntax validation, and type-checks before reporting completion.
- Ensure all created or modified files adhere to workspace boundaries and avoid uncommitted secrets.
- Verify tests or build commands exit cleanly with return code 0.