1. The architectural difference between MySQL and PostgreSQL is that MySQL is a relational database management system whereas, PostgresSQL is object-relational database management system.
2. MySQL is supported by the following operating system, Windows, Mac OS X, Linux, BSD, UNIX, z/OS, Symbian, AmigaOS. However, the PostgreSQL is supported by Windows, Mac OS X, Linux and BSD but not by UNIX, z/OS, Symbian, AmigaOS.
3. MySQL is the product of Oracle Corporation while PostgreSQL is a product of Global Development Group.
4. My SQL programming language is not extensible whereas, the programming language PostgreSQL is highly extensible.
5. In MySQL, the phpMyAdmin tool provides GUI and SQL interface. However, in PostgreSQL, the pgAdmin tool provides GUI and SQL interface.
6. In MySQL, Mysqldump, and XtraBackup tools provides backup. On the other hands, PostgresSQL provides complete backup online.
7. MySQL provides temporary tables but does not provide materialized view. However, PostgreSQL provides temporary table and also the materialized view.
8. MySQL does not offers data domain object whereas, PostgreSQL provide data domain object.