A cross-database join is an inner, left, right, or full outer join between two or more tables that are in different databases. You will often encounter multiple databases systems that house different information. Order information may be in an Amazon Redshift database while information about store locations may be in an SQL Server database. To join information from different sources, you will need to use a cross-database join.
There may be multiple reasons why data resides in different databases but that is beyond the scope of this chapter.
The four types of joins mentioned previously are available with cross-database joins. Cross-database joins require a multi-connection data source setup. This means that you need to ...
