SQL Performance Tunning

Question

Hi I am using Oracle 9i, i am having SQL Query like this which is taking mote time to execute , is there any alternate way to modify the same query with Rank and Partition by concepts? The tables(dw_csc_site_mappings smo, dw_csc_companies cco) having 14 million rows approx.
SELECT /*+ RULE */
smo.company_target_id, smo.customer_id
FROM dw_csc_site_mappings smo, dw_csc_companies cco
WHERE cco.company_target_id = smo.company_target_id
AND cco.global_target_id IS NOT NULL
GROUP BY smo.company_target_id, smo.customer_id
HAVING COUNT (*) =
(SELECT MAX (COUNT (*))
FROM dw_csc_site_mappings smi, dw_csc_companies cci
WHERE smo.customer_id = smi.customer_id
AND cci.company_target_id = smi.company_target_id
AND cci.global_target_id IS NOT NULL
GROUP BY smi.company_target_id, smi.customer_id)
ORDER BY 1 ASC

Answer 1

Analytics might help.
You should try to find a way to access those big tables only once instead of twice.
untested try
select company_target_id, customer_id, cnt
from (
   SELECT smo.company_target_id, smo.customer_id,
       count(*) cnt, max(count(*)) over (partition by smo.company_target_id, smo.customer_id order by count(*)) max_cnt
   FROM dw_csc_site_mappings smo, dw_csc_companies cco
   WHERE cco.company_target_id = smo.company_target_id
   AND cco.global_target_id IS NOT NULL
   GROUP BY smo.company_target_id, smo.customer_id
   ) v
WHERE v.cnt = v.max_cnt
ORDER BY 1 ASC