I'm able to get external data for simply queries like
select rtrim(app.sys_channel_cd), rtrim(app.mrkt_source_cd), rtrim(app.opr_application_nr), rtrim(apt.APPLICANT_NM), act.activity_dt
from heids.dly_activity act join heids.dly_application app
on act.application_id = app.application_id join...