There is a method of simulating SQL Server by using PostgreSQL. The extension is called "Babelfish": https://babelfishpg.org/
However, this extension requires modifications to the PostgreSQL source and building the PostgreSQL with Babelfish modifications from source. While it is a rather seamless process and goes on without much trouble, it is still much more complicated than installing the RPM or DEB packages, depending on your Linux distro of choice. Is there any chance that the Babelfish modifications will be adopted in the PostgreSQL source proper? From my DBA point of view, I didn't find any differences in the functionality of the PostgreSQL database itself. Amazon RDS incorporates that modification and allows creating Aurora PostgreSQL database with the Babelfish extension from the menu.
Hi there, I'm currently part of the Babelfish Open Source team.
Regarding the installation process it works, but is far from being smooth or ready to get OS packages
(there is, although, an ongoing work to get Docker images support in the upcoming months).
But most importantly, we won't see this into core anytime soon -- or maybe, we just won't see it as it is.
There is a patch for supporting protocol extensibility, but that requires considerable rework on the Babelfish
