sql-toolkit

# SQL Toolkit

Work with relational databases directly from the command line. Covers SQLite, PostgreSQL, and MySQL with patterns for schema design, querying, migrations, indexing, and operations.

## When to Use

- Creating or modifying database schemas
- Writing complex queries (joins, aggregations, window functions, CTEs)
- Building migration scripts
- Optimizing slow queries with indexes and EXPLAIN
- Backing up and restoring databases
- Quick data exploration with SQLite (zero setup)

## SQLite (Zero Setup)

SQLite is included with Python and available on every system. Use it for local data, prototyping, and single-file databases.

### Quick Start

```bash
# Create/open a database
sqlite3 mydb.sqlite

# Import CSV directly
sqlite3 mydb.sqlite ".mode csv" ".import data.csv mytable" "SELECT COUNT(*) FROM mytable;"

# One-liner queries
sqlite3 mydb.sqlite "SELECT * FROM users WHERE created_at > '2026-01-01' LIMIT 10;"

# Export to CSV
sqlite3 -header -csv mydb.sqlite "SELECT * FROM orders;" > orders.csv

# Interactive mode with headers and columns
sqlite3 -header -column mydb.sqlite
```

### Schema Operations

```sql
-- Create table
CREATE TABLE users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    email TEXT NOT NULL UNIQUE,
    name TEXT NOT NULL,
    created_at TEXT DEFAULT (datetime('now')),
    updated_at TEXT DEFAULT (datetime('now'))
);

-- Create with foreign key
CREATE TABLE orders (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    total REAL NOT NULL CHECK(total >= 0),
    status TEXT NOT NULL DEFAULT 'pending' CHECK(status IN ('pending','paid','shipped','cancelled')),
    created_at TEXT DEFAULT (datetime('now'))
);

-- Add column
ALTER TABLE users ADD COLUMN phone TEXT;

-- Create index
CREATE INDEX idx_orders_user_id ON orders(user_id);
CREATE UNIQUE INDEX idx_users_email ON users(email);

-- View schema
.schema users
.tables
```

## PostgreSQL

### Connection

```bash
# Connect
psql -h...