Buckets dynamic- series

Question

Hello all,
I am using Oracle 11g release 2.
I want to generate he buckets dynamically in chart.
For instance, sales figure is between 1 to 30. I want the number of buckets to be always be 5. If I need to be between 10-30 out of 1-30, I want evenly distributed in 5 intervals. That is 10,15,20,25,30.
If my series is 20-30 and number of buckets is 5 then 22,24,26,28,30.
Can it be done in single query.
Basically I am trying to identify the buckets in charts. it will always be 5 buckets, but based on the lower and upper limit the buckets has to be obtained. Please let me know how to attain this.
Thanks in advance,
jaggyam

Answer 1

Hi.
Here's an example using my prevous query:
WITH d AS
     SELECT 1 id, 10 val FROM dual UNION
     SELECT 2 id, 13 val FROM dual UNION
     SELECT 3 id, 15 val FROM dual UNION
     SELECT 4 id, 17 val FROM dual UNION
     SELECT 5 id, 18 val FROM dual UNION
     SELECT 6 id, 20 val FROM dual UNION
     SELECT 7 id, 23 val FROM dual UNION
     SELECT 8 id, 30 val FROM dual UNION
     SELECT 9 id, 35 val FROM dual UNION
     SELECT 10 id,40 val FROM dual UNION
     SELECT 11 id,42 val FROM dual UNION
     SELECT 12 id,43 val FROM dual UNION
     SELECT 13 id,46 val FROM dual UNION
     SELECT 14 id,49 val FROM dual UNION
     SELECT 15 id,50 val FROM dual
aux_intervals AS
     select
          (SELECT MAX(val) FROM d) -
          (level - 1) * FLOOR(((SELECT MAX(val) FROM d) - (SELECT MIN(val) FROM d))/(:number_buckets-1)) int
     from
     dual
     connect by level <= :number_buckets
intervals AS
     SELECT
          NVL(LAG(int) OVER (ORDER BY int),0) low,
          int up
     FROM aux_intervals
SELECT
     low,
     up,
     COUNT(*) cnt
FROM
     d,intervals i
WHERE
     d.val > low AND
     d.val <= up
GROUP BY low,up
ORDER BY 1;
:number_buckets = 5
LOW                    UP                     CNT                   
0                      10                     1                     
10                     20                     5                     
20                     30                     2                     
30                     40                     2                     
40                     50                     5                      Hope this helps.
Regards.