CREATE TABLE submission (submission_id NUMBER, scores NUMBER, author CLOB, college CLOB)
CREATE TABLE workshop (workshop_id NUMBER, date CLOB, venue CLOB, name CLOB)
CREATE TABLE acceptance (submission_id NUMBER, workshop_id NUMBER, result CLOB)

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
SELECT "T2"."author" FROM "acceptance" "T1" JOIN "submission" "T2" ON "T1"."submission_id" = "T2"."submission_id" GROUP BY "T2"."author" HAVING COUNT(DISTINCT "T1"."workshop_id") > 1