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Overview

The SQL Formatter beautifies SQL queries with proper indentation, keyword capitalization, and line breaks. Supports multiple database dialects including MySQL, PostgreSQL, SQLite, SQL Server, Oracle, and more.

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Use Cases

  • Query Beautification: Format minified or unformatted SQL for readability
  • Code Review: Standardize SQL formatting across team code
  • Documentation: Generate readable SQL examples for docs
  • Debugging: Make complex queries easier to understand
  • Learning: Study well-formatted SQL as a teaching aid
  • Code Generation: Format programmatically generated SQL

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Input Format

Unformatted or minified SQL: 
select u.id,u.name,u.email,o.order_id,o.total from users u inner join orders o on u.id=o.user_id where o.total>100 order by o.total desc;

CREATE TABLE products(id INT PRIMARY KEY,name VARCHAR(255),price DECIMAL(10,2),created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP);

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Output Format

Formatted SQL with proper indentation and structure: 
SELECT
  u.id,
  u.name,
  u.email,
  o.order_id,
  o.total
FROM
  users u
  INNER JOIN orders o ON u.id = o.user_id
WHERE
  o.total > 100
ORDER BY
  o.total DESC;

CREATE TABLE products (
  id INT PRIMARY KEY,
  name VARCHAR(255),
  price DECIMAL(10, 2),
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

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Supported Dialects

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Standard SQL (default)

Generic SQL formatting for most databases

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MySQL

SELECT
  *
FROM
  users
WHERE
  created_at > NOW() - INTERVAL 7 DAY
LIMIT 10;

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PostgreSQL

SELECT
  u.id,
  u.name,
  ARRAY_AGG(o.order_id) AS order_ids
FROM
  users u
  LEFT JOIN orders o ON u.id = o.user_id
GROUP BY
  u.id,
  u.name;

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SQLite

CREATE TABLE IF NOT EXISTS tasks (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  title TEXT NOT NULL,
  completed INTEGER DEFAULT 0
);

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SQL Server (T-SQL)

SELECT
  TOP 10 *
FROM
  dbo.users
WHERE
  status = 'active'
ORDER BY
  created_at DESC;

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Oracle PL/SQL

SELECT
  *
FROM
  users
WHERE
  ROWNUM <= 10
  AND status = 'active';

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Examples

select p.product_name,c.category_name,sum(oi.quantity) as total_sold,sum(oi.quantity*oi.unit_price) as revenue from order_items oi join products p on oi.product_id=p.id join categories c on p.category_id=c.id where oi.order_date between '2024-01-01' and '2024-12-31' group by p.product_name,c.category_name having sum(oi.quantity*oi.unit_price)>1000 order by revenue desc;

with monthly_sales as(select date_trunc('month',order_date) as month,sum(total) as sales from orders group by month),top_months as(select month,sales,rank() over(order by sales desc) as rank from monthly_sales)select * from top_months where rank<=3;

CREATE TABLE users(id SERIAL PRIMARY KEY,username VARCHAR(50) UNIQUE NOT NULL,email VARCHAR(255) UNIQUE NOT NULL,password_hash VARCHAR(255) NOT NULL,created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP);

select employee_id,department_id,salary,avg(salary) over(partition by department_id) as dept_avg,rank() over(partition by department_id order by salary desc) as dept_rank from employees;

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Formatting Features

  • Keyword Capitalization: SQL keywords in uppercase
  • Indentation: Consistent 2-space indentation
  • Line Breaks: Logical breaks for clauses (SELECT, FROM, WHERE, etc.)
  • Alignment: Aligned column lists and join conditions
  • Parentheses: Proper formatting for subqueries and functions
  • Operator Spacing: Consistent spacing around operators (equals, less than, greater than, etc.)
  • Comment Preservation: Maintains SQL comments

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Implementation Details

From lib/tools/engine.ts:677-681: 
case 'sql-formatter': {
  const language = action === 'default' ? 'sql' : action;
  const { format: formatSql } = await import('sql-formatter');
  return { output: formatSql(input, { language: language as any }) };
}
Uses the sql-formatter library with dialect-specific parsing for accurate formatting across different SQL variants.
For best results, select the specific dialect that matches your database. Dialect-specific formatting handles vendor-specific syntax and keywords correctly.
The formatter preserves SQL logic but may change query structure. Always test formatted queries in a development environment before using in production.

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