Hi!
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.
Regards
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Mladen Gogala
Database Consultant
Tel: (347) 321-1217
https://dbwhisperer.wordpress.com