SQL Split by space

SELECT  t.id,
    CASE  WHEN  a.l = 1
              THEN  substr(message, 1, instr(message,' ',1,a.l)-1)
              ELSE  substr(message, instr(message,' ',1,a.l-1)+1,
                              CASE WHEN instr(message,' ',1,a.l)-instr(message,' ',1,a.l-1)-1 > 0
                                   THEN instr(message,' ',1,a.l)-instr(message,' ',1,a.l-1)-1
                                   ELSE length(message)
                                   END
     )
        END  final_message
FROM    mqtt_event t,
        ( SELECT level l
          FROM DUAL
          CONNECT BY LEVEL <=
                (
                SELECT Max(length(message) - length(replace(message,' ',''))+1) FROM  mqtt_event
                )
        ) a
WHERE   length(message) - length(replace(message,' ',''))+1 >= a.l
and t.topic  like '%person%'
order by t.id desc, a.l;