Can I compare the difference between two databases in SQL

It can be useful when troubleshooting to compare a copy of a customer's data to the demo data or an old copy of their own data that doesn't exhibit the problem you're investigating.

There are many software packages available that can be used to compare the differences between two databases, Sage is not able to recommend any particular solution. Here are some examples of the options available:

https://dbcomparer.com/ - A freeware package

https://github.com/OpenDBDiff/OpenDBDiff - Open source 

https://sqldbtools.com/tools/sqldbdiff - Freeware version available

https://visualstudio.microsoft.com/vs/features/ssdt/ - For use with Visual studio