Dear all

--I have union query in each union there are few common tables , so i want to keep the result of this common tables in temp table and then want to use them in different union.
--i have one sp(stored proc) which brings two result sets both query have few comman tables, so i want to keep the result of this common tables in temp table and then want to use them in two different
query in same sp(stored proc).

please note: i do not want to use global temp tables.
yours sincerely.

use a view & avoid duplicating data

I see developers trying to "cache" data all the time. My advice is, don't try to cache the data yourself. Write your SQL to solve the query each time. Oracle has a really out of this world data caching mechanism that works much better than anything that you will come up with.

I would recommend that you read Oracle Database Concepts: Buffer Cache which will give you some idea of how Oracle "caches" your data for you.
I would seriously recommend you get your hands on a book by Tom Kyte called Exper Oracle Database Architecture, in particular chapter 4 on memory structures. He explains it all very well.