-- Database schema
| workshop : Workshop_ID [ INT ] primary_key , Date [ TEXT ] , Venue [ TEXT ] , Name [ TEXT ] | submission : Submission_ID [ INT ] primary_key , Scores [ INT ] , Author [ TEXT ] , College [ TEXT ] | Acceptance : Submission_ID [ INT ] primary_key Acceptance.Submission_ID = submission.Submission_ID , Workshop_ID [ INT ] Acceptance.Workshop_ID = workshop.Workshop_ID , Result [ TEXT ] |
-- -- Which authors have submitted to more than one workshop?

SELECT T2.Author FROM acceptance AS T1 JOIN submission AS T2 ON T1.Submission_ID  =  T2.Submission_ID GROUP BY T2.Author HAVING COUNT(DISTINCT T1.workshop_id)  >  1;