Помимо NOT Exists
вы также можете LEFT JOIN/ IS NULL
это предполагает, что все соединяемые поля НЕ НУЛЬЫ
SELECT vt.DROPPER_ID, vt.BEGIN_DT, vt.END_DT
FROM VACATION_TEST vt
LEFT JOIN (
SELECT DROPPER_ID, BEGIN_DT, END_DT
FROM VACATION_TEST
MINUS
SELECT REPORTER_VACATION.REPORTER, REPORTER_VACATION.BEGIN_DT, REPORTER_VACATION.END_DT
FROM REPORTER_VACATION, DROPPER
WHERE DROPPER.REPORTER = REPORTER_VACATION.REPORTER AND PROJECT_CD = 'INTL' ) ni
ON vt.DROPPER_ID = ni.DROPPER_ID
AND vt.BEGIN_DT =ni.BEGIN_DT
AND vt.END_DT = ni.END_DT
WHERE ni.DROPPER_ID is null