The CData ODBC Driver for Oracle Eloqua 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 Contact.Name, Activity_EmailClickThrough.CreatedAt FROM Contact, Activity_EmailClickThrough WHERE Contact.ID=Activity_EmailClickThrough.ContactID

Left Join

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

SELECT Contact.Name, Activity_EmailClickThrough.CreatedAt FROM Contact LEFT OUTER JOIN Orders ON Contact.ID=Activity_EmailClickThrough.ContactID