The CData Excel Add-In for Zoho Projects 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 t.Id, t.Name, t.Key, c.Content, c.AddedPersonName FROM Tasks t INNER JOIN TaskComments c ON t.Id = c.TaskId

Left Join

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

 SELECT t.Id, t.Name, t.Key, c.Content, c.AddedPersonName FROM Tasks t LEFT JOIN TaskComments c ON t.Id = c.TaskId