duckdb-en

Files (3)

• README.md
• SKILL.md
• _meta.json

SKILL.md (first lines)

# DuckDB CLI Specialist

Helps with data analysis, SQL queries and file conversion via DuckDB CLI.

## Quick Start

### Read data files directly with SQL
```bash
# CSV
duckdb -c "SELECT * FROM 'data.csv' LIMIT 10"

# Parquet
duckdb -c "SELECT * FROM 'data.parquet'"

# Multiple files with glob
duckdb -c "SELECT * FROM read_parquet('logs/*.parquet')"

# JSON
duckdb -c "SELECT * FROM read_json_auto('data.json')"
```

### Open persistent databases
```bash
# Create/open database
duckdb my_database.duckdb

# Read-only mode
duckdb -readonly existing.duckdb
```

## Command Line Arguments

### Output formats (as flags)
| Flag | Format |
|------|--------|
| `-csv` | Comma-separated |
| `-json` | JSON array |
| `-table` | ASCII table |
| `-markdown` | Markdown table |
| `-html` | HTML table |
| `-line` | One value per line |

### Execution arguments
| Argument | Description |
|----------|-------------|
| `-c COMMAND` | Run SQL and exit |
| `-f FILENAME` | Run script from file |
| `-init FILE` | Use alternative to ~/.duckdbrc |
| `-readonly` | Open in read-only mode |
| `-echo` | Show commands before execution |
| `-bail` | Stop on first error |
| `-header` / `-noheader` | Show/hide column headers |
| `-nullvalue TEXT` | Text for NULL values |
| `-separator SEP` | Column separator |

## Data Conversion

### CSV to Parquet
```bash
duckdb -c "COPY (SELECT * FROM 'input.csv') TO 'output.parquet' (FORMAT PARQUET)"
```

### Parquet to CSV
```bash
duckdb -c "COPY (SELECT * FROM 'input.parquet') TO 'output.csv' (HEADER, DELIMITER ',')"
```

### JSON to Parquet
```bash
duckdb -c "COPY (SELECT * FROM read_json_auto('input.json')) TO 'output.parquet' (FORMAT PARQUET)"
```

### Convert with filtering
```bash
duckdb -c "COPY (SELECT * FROM 'data.csv' WHERE amount > 1000) TO 'filtered.parquet' (FORMAT PARQUET)"
```

## Dot Commands

### Schema inspection
| Command | Description |
|---------|-------------|
| `.tables [pattern]` | Show tables (with LIKE pattern) |
| `.schema [table]` | Show CREATE statements |
| `.databases` | Show attached databases |

### Output control
| Command | Description |
|---------|-------------|
| `.mode FORMAT` | Change output format |
| `.output file` | Send output to file |
| `.once file` | Next output to file |
| `.headers on/off` | Show/hide column headers |
| `.separator COL ROW` | Set separators |

### Queries
| Command | Description |
|---------|-------------|
| `.timer on/off` | Show execution time |
| `.echo on/off` | Show commands before execution |
| `.bail on/off` | Stop on error |
| `.read file.sql` | Run SQL from file |

### Editing
| Command | Description |
|---------|-------------|
| `.edit` or `\e` | Open query in external editor |
| `.help [pattern]` | Show help |

## Output Formats (18 available)

### Data export
- **csv** - Comma-separated for spreadsheets
- **tabs** - Tab-separated
- **json** - JSON array
- **jsonlines** - Newline-delimited JSON (streaming)

### Readable formats
- **duckbox** (default) - Pretty ASCII with unicode box-drawing

From aAAaqwq/AGI-Super-Team, MIT.

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