The CData ADO.NET Provider for HDFS 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 c.Owner, o.OwnerRead, o.OwnerWrite, o.OwnerExecute FROM Files c INNER JOIN Permissions o ON c.FullPath = o.FullPath

Left Join

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

 SELECT c.Group, o.GroupRead, o.GroupWrite, o.GroupExecute FROM Files c LEFT JOIN Permissions o ON c.FullPath = o.FullPath