So its not the same event - is a sequence of 'unrelated' events with the same title?
That isn't trivial I'm afraid. Assuming they are not repeating events with separate signups per event
Something like this
MAY
SELECT atdees.*, atdce.id, det.evdet_id FROM onjqe_jev_attendees as atdees
INNER JOIN onjqe_jev_attendance as atdce on atdees.at_id = atdce.id
INNER JOIN onjqe_jevents_vevent as evt on atdce.ev_id = evt.ev_id AND atdce.allrepeats = 1
INNER JOIN onjqe_jevents_vevdetail as det on evt.detail_id = det.evdet_id
WHERE det.summary = 'test'