The CData Cmdlets PowerShell Module 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