ĮDIT: To solve my problem i did the fist part of the third step at this link, which was: Download the appropriate version of SSDTSetup. VS2019 SQL schema comparison error: Value cannot be null. When i use the Typical installation, ssdt installs fine, but it installs VS at c:/, and i need it installed at "D:/". I checked the ssdt option at the setup, and the only thing i did was change the default installation directory from c:/ to d:/ (don't know if it changes anything). However if you have SQL Server 2012, SQL Server Data Tools are available in the installation media (unlike SQL 2014 where it has to be manually downloaded & installed).
This will install Visual Studio 2013 x32. SQL Server 2014 Developer Edition Free Download Latest Version for Windows. I've installed Visual Studio 2015, but the ssdt features are missing as you can see below So if you have 圆4 SQL Server 2014, you can only install SQL Server Data Tools x32 in a new instance configuration.