DELETE FROM EMP_INVALID
WHERE EMP_CODE IN (
SELECT 
 v.EMP_CODE
FROM 
EMP v
LEFT JOIN (SELECT EMP_CODE, USER_UPDATE_DATETIME AS deleted_at FROM EMP_INVALID) i
ON v.EMP_CODE = i.EMP_CODE
WHERE deleted_at IS NOT NULL AND (NOT (VALID_FLG = "1" AND USER_UPDATE_DATETIME >= deleted_at ))
)