The CData Power BI Connector for Microsoft Teams supports standard SQL joins like the following examples.

Inner Join

An inner join selects only rows from both tables that match the join condition:

SELECT Teams.displayName, Channels.desciption FROM Teams, Channels WHERE Teams.Id=Channels.TeamId

Left Join

A left join selects all rows in the FROM table and only matching rows in the JOIN table:

SELECT Groups.displayName, Teams.Description FROM Groups LEFT OUTER JOIN Teams ON Groups.Id=Teams.GroupId