Linking reports together via an in-memory join or union allows you to create powerful reports with multiple aggregates or to combine data from multiple databases to generate a single virtual data source for reporting.
This can be a very useful method when you have a requirement for creating value comparisons against dates, locations, or any other parameter and formulas need to be executed per parameter. A single report can be created for each unique aggregate or calculation and then data can be linked together via the shared value in each report.
Another common use case is when you need to combine similar data from multiple data sources. This is referred to as a Union. An example is you have multiple help desk systems, all with separate databases, and you wish to pull together a common report that shows a list of tickets by a common set of fields (ticket number, category, assignee, requester, etc). By creating a report from each database, the Linked Reports feature allows you to merge or union all the data into a single report.
An alternative to doing in-memory joins or unions of data is to organize the data into a view at the database level. For complex reports or in environments where less technical users are building reports, that is our recommended approach as joining or unioning reports is a more advanced concept.
This video walks you through the process of creating a Linked Report: