Serial No. comes scrambled

Question

I have got the following query :
select
htmldb_item.display_and_save(1, rownum) "Sr. No.",
htmldb_item.display_and_save(2, emp_name) "Emp Name",
htmldb_item.display_and_save(3, dept_id) "Dept No.",
from emp_master
where (emp_name like :P158_EMP_NAME or :P158_EMP_NAME is null)
and (dept_id like :P158_DEPT_ID or :P158_DEPT_ID is null)
and ((emp_f_er = 'Y' or emp_f_ig = 'Y') or :P158_ERROR = 2)
and (to_date(emp_fl_ts) between :p158_from and :p158_to or :p158_from is null)
and (bpclpb_f_a like :p158_active or :p158_active like '3' or :p158_active is null)
order by emp_name, dept_id
The problem with the above query is that the Serail Number (ROWNUM) values come scrambled.
It works fine in oracle sqlplus.. but am not able to understand the problem over here.
Thnx in advance
Ameya

Answer 1

Because as far as I know, first the records are
fetched in a sorted order and then the
rownum values are assigned.Thats why the inline view is used for Top-N queries. Order by gets applied last. So it can only be safely used after the entire set it ordered.
You can also use analytics which I like a lot better - it would save you from having to do the inline view on normal occassions (i dont think it would work with htmldb_item directly)
Untested btw
SELECT htmldb_item.display_and_save(1, rnum) "Sr. No.",
       htmldb_item.display_and_save(2, emp_name) "Emp Name",
       htmldb_item.display_and_save(3, dept_id) "Dept No.",
  FROM (SELECT emp_name,
               dept_id,
               emp_f_er,
               emp_f_ig,
               bpclpb_f_a,
               row_number() over(ORDER BY emp_name, dept_id) rnum
          FROM emp_master) emp
WHERE (emp_name LIKE :P158_EMP_NAME OR :P158_EMP_NAME IS NULL) AND
       (dept_id LIKE :P158_DEPT_ID OR :P158_DEPT_ID IS NULL) AND
       ((emp_f_er = 'Y' OR emp_f_ig = 'Y') OR :P158_ERROR = 2) AND
       (to_date(emp_fl_ts) BETWEEN :p158_from AND :p158_to OR
       :p158_from IS NULL) AND
       (bpclpb_f_a LIKE :p158_active OR :p158_active LIKE '3' OR
       :p158_active IS NULL)
ORDER BY emp_name,
          dept_id