The CData ADO.NET Provider for Asana 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 P.Id,P.Name,P.color,PS.Id,PS.Title FROM Projects P INNER JOIN ProjectStatuses PS ON P.Id=PS.ProjectId

Left Join

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

SELECT P.Id,P.Name,P.color,PS.Id,PS.Title FROM Projects P LEFT JOIN ProjectStatuses PS ON P.Id=PS.ProjectId