Hi Experts,
I am having problem with sql query. I am using the sql query for generation of reports . The query is using NOT IN clasue. The
query is taking aroound 1 hour to run. Even after creating index on it,
no use. Can any one help me to optimize the query.

Query:

SELECT COUNT(1) FROM ITEM_MASTER
WHERE ITEM_MASTER.ITEM_NUMBER
NOT IN (SELECT ITEM_MASTER.ITEM_DESC1
FROM
ITEM_MASTER,
DB_MASTER DB_MASTER_ITEM
WHERE
ITEM_MASTER.DB_CODE=DB_MASTER_ITEM.DB_CODE
AND
DB_MASTER_ITEM.REPORT_REGION_NAME = 'AMERICAS')



Thanks,
Parag