Database Tools for Developers

Build SQL queries visually, format messy SQL, design schemas, and access quick reference cheat sheets. Free tools, no signup required.

Query Builder Format SQL

SELECT u.name, COUNT(o.id)
FROM users u
JOIN orders o ON u.id = o.user_id
WHERE o.date > '2024-01-01'
GROUP BY u.name
HAVING COUNT(o.id) > 5
ORDER BY COUNT(o.id) DESC;

Visual SQL Query Builder

Build queries by filling in the form - SQL generated automatically

Operation

Table

Columns

WHERE

ORDER BY

LIMIT

JOIN

GROUP BY

Click the query to copy to clipboard

SQL Formatter

Paste messy SQL and get beautifully formatted output

select u.name, u.email, count(o.id) as order_count from users u inner join orders o on u.id = o.user_id where u.active = 1 and o.created_at > '2024-01-01' group by u.name, u.email having count(o.id) > 3 order by order_count desc limit 50

Schema Design Best Practices

Primary Keys

Always use auto-incrementing integer or UUID primary keys. Avoid natural keys (like email) as PKs - they can change.

Normalization

Aim for 3NF (Third Normal Form) for most cases. Denormalize only when you have proven performance needs.

Indexes

Index columns used in WHERE, JOIN, and ORDER BY. Composite indexes should match query column order. Don't over-index.

Security

Always use parameterized queries. Never concatenate user input into SQL. Apply least-privilege database roles.

SQL Quick Reference

JOINS

INNER JOIN
LEFT JOIN
RIGHT JOIN
FULL OUTER JOIN
CROSS JOIN

AGGREGATES

COUNT(*)
SUM(column)
AVG(column)
MAX(column)
MIN(column)

STRING

CONCAT(a, b)
UPPER(str)
LOWER(str)
TRIM(str)
SUBSTRING(str,s,l)

DATE

NOW()
CURDATE()
DATE_ADD(d, n)
DATEDIFF(a, b)
DATE_FORMAT(d, f)