UPDATE school a
SET a.flag = 'Y'
WHERE 1=1
AND EXISTS (SELECT 1
FROM student b
WHERE b.app_id = 1
AND b.source_id = a.id
AND b.code = CASE WHEN a.type IN ('1', '3') THEN 'junior'
WHEN a.type NOT IN ('1', '3') THEN 'senior'
END
)
;