PocketQuery for Confluence is an app that allows users to retrieve data from external data sources and display the data within Confluence. Data sources can be SQL databases or arbitrary REST APIs and the access is encapsulated in a way that easily works with your security standards.
PocketQuery comes with a macro that can be embedded into any Confluence page. The user simply selects the desired query and enters parameters if necessary. After saving, the macro fetches and displays the data. Queries are managed within the PocketQuery Administration interface, which is only available to Confluence users with appropriate permissions.
And there is a lot more to discover! How about adding your query result to the Confluence search index? Or let the user change parameters dynamically through an automatically rendered form?