SQL & PL/SQL

Hi

can anyone tell me why we are using No_Filtering hint?

This query is Retriving extra rows when hints not applied.What is the reason.

Select /*+ No_Filtering */ *
from (select /*+ No_Filtering */
true_name, true_name_cmprsd, jurisname, entityids, ht,
max(ht) over(partition by true_name_cmprsd) ht_1
from (select /*+ No_Filtering */true_name, true_name_cmprsd,
LTRIM(SYS_CONNECT_BY_PATH(entity_id, '; '), '; ') AS EntityIds,
juris_short_name JurisName,
LEVEL HT

FROM (select /*+ No_Filtering */e.true_name, e.TRUE_NAME_CMPRSD, j.JURIS_SHORT_NAME, e.entity_id,
ROW_NUMBER() OVER(PARTITION BY TRUE_NAME_CMPRSD ORDER BY ENTITY_ID) AS curr,
ROW_NUMBER() OVER(PARTITION BY TRUE_NAME_CMPRSD ORDER BY ENTITY_ID) - 1 AS prev
from SIV_JURISDICTION j, arv_entity e
where e.ENTITY_STATUS_CD = 2002 and
e.DOM_JURIS_ID = j.JURIS_ID and juris_id = 8)
connect by prev = PRIOR curr AND true_name_cmprsd = PRIOR true_name_cmprsd
start with curr = 1)
WHERE ht > 1)
where ht = ht_1
order by upper(true_name)


Thanks in advance...