Ranking query Required ( as not in oracle built in rank functions )

Question

Hai I have facing some kind of problem with Ranking using sql, i want different ranking as not in oracle built in functions ,
Please help me
for Example, i am showing the sample data what i required Exactly
if any student obtains the same marks rank should be bottom rank of the students who got same rank which should cummulate top students rank
Ranking Procedure - 1
=========================
sno Student Marks Rank
=========================
1 x00013 50 2
2 x00021 50 2
3 x00012 49 5
4 x00001 49 5
5 x00002 49 5
6 x00033 48 10
7 x00034 48 10
8 x00015 48 10
9 x00088 48 10
10 x00051 48 10
11 x00044 47 11
12 x00041 48 12
=======================
Ranking Procedure - 2
=========================
sno Student Marks Rank
=========================
1 x00013 50 1
2 x00021 50 1
3 x00012 49 3
4 x00001 49 3
5 x00002 49 3
6 x00033 48 6
7 x00034 48 6
8 x00015 48 6
9 x00088 48 6
10 x00051 48 6
11 x00044 47 7
12 x00041 48 8
=======================
regards
Mahesh

Answer 1

Why are you excluding Oracle built in functions? The results of "Ranking Procedure 2" would appear to just be the result of
SELECT sno, student, marks, RANK() OVER (ORDER BY marks DESC) rnk
  FROM your_tablei.e.
  1  with x as (
  2  select 1 sno, 13 student, 50 marks from dual
  3  union all
  4  select 2, 21, 50 from dual
  5  union all
  6  select 3, 12, 49 from dual
  7  )
  8  select sno, student, marks, rank() over (order by marks desc) rnk
  9*   from x
SCOTT @ jcave102 Local> /
       SNO    STUDENT      MARKS        RNK
         1         13         50          1
         2         21         50          1
         3         12         49          3I would probably write a custom analytic function to get the results of your first ranking procedure. Though I imagine you could get the same results in pure SQL, a well-named custom aggregate function would seem to be easier to understand (though the pure SQL solution may well be somewhat more efficient).
Justin