Is it a good idea to join data from two different databases?

I am building an application that requires a lot of tables in one database and while the joining and aggregation of data is really nice and seamless, I am starting to wonder if I am creating too many tables in one database rather than organizing better by creating multiple databases. 1. Is this standard practice in enterprise level companies? 2. How do you usually join data from two different databases if its normal to do so? 3. Does this cause latency issues? Any help or guidance would help,