SQL Playground
Write and execute SQL queries directly in your browser. Pre-loaded with a sample database featuring departments, employees, and orders tables. No signup or backend required — powered by SQLite compiled to WebAssembly.
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Free Online SQL Playground — Practice SQL Queries in Your Browser
What is the SQL Playground?
Code Visualizer's SQL Playground is a free, browser-based SQL editor that lets you write and run SQL queries instantly. Powered by SQLite compiled to WebAssembly (sql.js), it runs entirely in your browser with zero setup — no database installation, no server, no signup. It's the fastest way to practice SQL queries, prepare for technical interviews, or learn SQL from scratch.
What SQL Features Are Supported?
Execute any standard SQL including SELECT, INSERT, UPDATE, DELETE, CREATE TABLE, ALTER TABLE, JOIN (INNER, LEFT, RIGHT, CROSS), GROUP BY, HAVING, ORDER BY, subqueries, Common Table Expressions (CTEs), window functions (RANK, ROW_NUMBER, SUM OVER), CASE expressions, and aggregate functions. The playground supports the full SQLite SQL dialect.
Pre-loaded Sample Database
The playground comes pre-loaded with a realistic sample database containing departments (id, name, location, budget), employees (id, name, department, salary, hire_date, email), and orders (id, employee_id, product, amount, order_date) tables. This schema is designed to practice real-world SQL patterns like JOINs, aggregations, and analytical queries.
Perfect for Interview Prep
SQL is one of the most tested skills in data engineering, backend, and data science interviews. Use the SQL Playground to practice common interview patterns: finding the second-highest salary, department-level aggregations, self-joins, running totals with window functions, and complex subqueries. Build muscle memory by writing queries from scratch.
Frequently Asked Questions
Is this SQL Playground free to use?
Yes, the SQL Playground is completely free. It runs entirely in your browser using WebAssembly — no account, no server, no limits.
What SQL dialect does it support?
The playground uses SQLite (via sql.js), which supports standard SQL including JOINs, subqueries, CTEs, window functions, and more. Most SQL interview questions can be practiced here.
Is my data saved?
Data exists only in your browser session. Refreshing the page resets the database to its default state. Use the Reset DB button to restore the original sample data at any time.
Can I create my own tables?
Yes! You can run CREATE TABLE, INSERT, UPDATE, DELETE, and any DDL/DML statements. The schema explorer updates automatically to show your new tables.