Different types of SQL

PostgreSQL

SQL is Structured Query Language is a database computer language designed for managing data in relational database management systems (RDBMS).

PostgreSQL is an object-relational database management system (ORDBMS).[1] It is released under a BSD-style license and is thus free software. As with many other open-source programs, PostgreSQL is not controlled by any single company, but has a global community of developers and companies to develop it.

SQLite is an ACID-compliant embedded relational database management system contained in a relatively small (~225 KB[1]) C Programming library. The source code for SQLite is in the public domain.

MySQL

MySQL (pronounced /maɪˌɛskjuːˈɛl/[1] My S-Q-L, or "My sequel" /maɪˈsiːkwəl/) is a relational database management system (RDBMS)[2] which has more than 6 million installations. [3] MySQL stands for "My Structured Query Language". The program runs as a server providing multi-user access to a number of databases.