The CData Excel Add-In for Google Data Catalog 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 s.DatasetName, s.Type, t.TableName, t.ResourceName FROM Tables t INNER JOIN Schemas s ON s.DatasetName = t.DatasetName

Left Join

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

SELECT s.DatasetName, s.Type, t.TableName, t.ResourceName FROM Tables t LEFT JOIN Schemas s ON s.DatasetName = t.DatasetName