To generate sql string of desired row using function.

Question

Hi l,
I return the below query to get sum of vehicles which falls between the specific weight ranges.
It returns 20 rows( As I selected 4 classification vehicles).I was expect only 4 rows .One row for each classification of vehicles.
Is there a way if do some loop or decode in my function logic?
will tht work?
"(This is only smple. In my real appilication, if I use 15 classification vehicles it returns 320 rows. But i expect only 16 rows - 0 to 15 one row for each classification .Duirng runtime I'm getting an error as buffer string too small)"
How could I solve this?
I use this query inside a function and I call that function in a dynamic sql.
SELECT 'SUM('
    || 'CASE '
    || 'WHEN weight_report_data.weight >=  '|| repo_range_param.min_value ||' 
        AND weight_report_data.weight   <       repo_range_param.max_value
        THEN weight_report_data.weight_count '   
    || 'ELSE 0 '
    || 'END '
    || ') "Class ' || repo_param.r_value || '" '   
      FROM repo_param
      JOIN repo_range_param
        ON repo_param.r_id = repo_range_param.r_id
     WHERE repo_param.r_id    = 1
       AND repo_param.r_group = 'class'
       AND repo_param.r_name  = 'class'
       AND repo_range_param.r_group = 'gvw'
       AND repo_range_param.r_name  = 'gvw'
     ORDER BY CAST(repo_param.r_value AS NUMBER) ASC;
"sample sql string output when I run the above query "
SUM(CASE WHEN weight_report_data.weight >=10
         AND weight_report_data.weight  <15
        THEN weight_report_data.weight_count ELSE 0 END ) "Class 0"
SUM(CASE WHEN weight_report_data.weight >=15
         AND weight_report_data.weight  <20
        THEN weight_report_data.weight_count ELSE 0 END ) "Class 1"
SUM(CASE WHEN weight_report_data.weight >=5
         AND weight_report_data.weight  <10
        THEN weight_report_data.weight_count ELSE 0 END ) "Class 2"
SUM(CASE WHEN weight_report_data.weight >=20
         AND weight_report_data.weight  <25
        THEN weight_report_data.weight_count ELSE 0 END ) "Class 3"
"sample data for the tables involved"
CREATE  TABLE weight_report_data
start_date_time       TIMESTAMP      NOT NULL,
end_date_time         TIMESTAMP      NOT NULL,
weight                NUMBER(12,0)   NOT NULL,
weight_count          NUMBER(12,0)   NOT NULL
INSERT INTO weight_report_data(start_date_time, end_date_time, weight, weight_count)
       VALUES('01-JUL-08 12:00:00','03-JUL-08 12:00:00',4,5);
INSERT INTO weight_report_data(start_date_time, end_date_time, weight, weight_count)
       VALUES('01-JUL-08 12:00:00','03-JUL-08 12:00:00',3,1);
INSERT INTO weight_report_data(start_date_time, end_date_time, weight, weight_count)
       VALUES('01-JUL-08 12:00:00','03-JUL-08 12:00:00',8,6);
INSERT INTO weight_report_data(start_date_time, end_date_time, weight, weight_count)
       VALUES('01-JUL-08 12:00:00','03-JUL-08 12:00:00',25,9);
CREATE  TABLE repo_param
R_ID       NUMBER(12,0),
R_GROUP     VARCHAR2(10),
R_NAME     VARCHAR2(10),
R_VALUE     VARCHAR2(10)
INSERT INTO repo_param(r_id, r_group, r_name, r_value)
       VALUES(1,'class','class',0);
INSERT INTO repo_param(r_id, r_group, r_name, r_value)
       VALUES(1,'class','class',1);
INSERT INTO repo_param(r_id, r_group, r_name, r_value)
       VALUES(1,'class','class',2);
INSERT INTO repo_param(r_id, r_group, r_name, r_value)
       VALUES(1,'class','class',3);
CREATE  TABLE repo_range_param
R_ID       NUMBER(12,0),
R_GROUP     VARCHAR2(10),
R_NAME     VARCHAR2(10),
MIN_VALUE NUMBER(3,0),
MAX_VALUE     NUMBER(3,0)
INSERT INTO repo_range_param(r_id, r_group, r_name, min_value, max_value)
       VALUES(1,'gvw','gvw',0,5);
INSERT INTO repo_range_param(r_id, r_group, r_name, min_value, max_value)
       VALUES(1,'gvw','gvw',5,10);
INSERT INTO repo_range_param(r_id, r_group, r_name, min_value, max_value)
       VALUES(1,'gvw','gvw',10,15);
INSERT INTO repo_range_param(r_id, r_group, r_name, min_value, max_value)
       VALUES(1,'gvw','gvw',15,20);
       INSERT INTO repo_range_param(r_id, r_group, r_name, min_value, max_value)
       VALUES(1,'gvw','gvw',20,25);
Thanks in advance
Edited by: user10641405 on Jun 18, 2009 4:10 PM
Edited by: user10641405 on Jun 18, 2009 4:15 PM
Edited by: user10641405 on Jun 18, 2009 4:15 PM
Edited by: user10641405 on Jun 18, 2009 4:16 PM
Edited by: user10641405 on Jun 18, 2009 4:17 PM
Edited by: user10641405 on Jun 18, 2009 7:47 PM
Edited by: user10641405 on Jun 19, 2009 4:15 PM

Answer 1

Say you have a 3 tables
Table name Description rowcount()
============================================================================
weight_report_data report table having weights and counts 4
repo_param having id column gives different classes 4
repo_range_param is detail table of repo_param with id 4
          as foreign key and defines weight
          min max ranges.
Now you need to report
per class how many weights weights are there ?
--not understood report id clearly in relation to weight_report_data
step1:
need to map each row of weight_report_data againist its class.
select wrd.weight,wrd.weight_count,(select rp.class||rp.value
from repo_range_param rrp,
          repo_param rp
where rrp.id= rp.id
and rp.id=1 -- add your other join condition
and wrd.weight between rrp.min and rrp.max ) class_nm
from weight_report_data wrd ;
This will give 4 rows , i.e for each row in wrd it tells which class it falls.
now you want to group by class_nm to get sum or count of weights.
step2:
select class_nm,sum(weight), count(weight), sum(weight_count)
from (
select wrd.weight,wrd.weight_count,(select rp.class||rp.value
from repo_range_param rrp,
          repo_param rp
where rrp.id= rp.id
and rp.id=1 -- add your other join condition
and wrd.weight between rrp.min and rrp.max ) class_nm
from weight_report_data wrd ) wrd_classnm
group by class_nm;
I hope this helps .
suggestion: first analyse and breakdown into stpes how you r going to do if you do by hand and then translate into sql and then optimise