Sql rewrite help

Question

I have a select statemnet like below.. it currently returns 3 rows. I want the the last value from this query below. so i want only "4" returned from this query. How to achieve it ? Thanks for the help.
SQL
SELECT  col6
FROM  TableA
WHERE  col1=12
AND    col2='B'
AND    col3='001'
AND    col4='455'
AND    col5='666'
ORDER BY col1, col2, col3,col5, col4 desc
curent output
1
5
4
expected output
4

Answer 1

Etbin wrote:
Maybe NOT TESTED!
select col6
  from (select col6,rownum rn
          from (SELECT col6
                  FROM TableA
                 WHERE col1 = 12
                   AND col2 = 'B'
                   AND col3 = '001'
                   AND col4 = '455'
                   AND col5 = '666'
                 ORDER BY col1,col2,col3,col5,col4 desc
         order by rn desc
where rownum = 1
Regards
Etbin
Hi,
Please correct me if I'm wrong, (I didn't test your solution ), but I think there could be a problem in your query which has the following form:
SELECT col6       -
FROM
     SELECT col6, rownum rn     -- 1st subquery
     FROM
           SELECT col6          -- 2nd subquery
           FROM     . . .
           ORDER BY . . .
     ORDER BY rn DESC
WHERE rownum = 1
The global query is a top-n-reporting so the order defined in "1st subquery" is conserved within the global query thanks to WHERE rownum = 1, however the order defined by the ORDER BY clause of the "2nd subquery" is not necessarily relevant inside "1st subquery" as there is no top-n structure at this level (inside 1st subquery). In otherwords rownum will not enumerate rows based on the order in the 2nd subquery that the OP defined, that is ORDER BY col1,col2,col3,col5,col4 desc,
Regards,
Dariyoosh