Which service types had both success and failure for their event details?
SELECT T1.service_type_code FROM services AS T1 JOIN EVENTS AS T2 ON T1.service_id  =  T2.service_id WHERE T2.event_details  =  'Success' INTERSECT SELECT T1.service_type_code FROM services AS T1 JOIN EVENTS AS T2 ON T1.service_id  =  T2.service_id WHERE T2.event_details  =  'Fail'
service types that had both success and failure refers to finding service_type_code present in both success and fail event_details using INTERSECT;