It is a SQL playground which allows to test SQL online. Run SQL queries for SQLite, MySQL and PostgreSQL databases. Share snippets.
Online SQL Editor - Free Online SQL Editor
SQL Fiddle - A tool for easy online testing and sharing of database problems and their solutions.
Rextester - Online compiler for many languages, including MySQL
JSFiddle - Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor.
DB Fiddle - An online tool for testing, sharing and collaborating on SQL snippets
SQLZOO - SQLZoo includes tutorials and reference to support people learning SQL. It features: