Union All vs. View Creation Problem

Question

Here is my problem basicly;
I have three table.
select * from table1;
select * from table2;
select * from table3;
I need to create one view by combining those tables with 'union all' word.
create or replace view view1 as
select * from table1;
union all
select * from table2;
union all
select * from table3;
Then, I want to write a query as;
select * from view1 where column1 = x;
When I did this, view1 first combines all the rows of the tables, then searches x value in all the data. That's OK. However I want to first search x value in the tables, and combine the results of each table and get the result rows.
I mean, my query "select * from view1 where column1 = x;" need to act as
select * from table1;
column1 = x
union all
select * from table2;
column1 = x
union all
select * from table3;
column1 = x
How can I do this?
Thanks everyone..

Answer 1

SnigRO
I think what you mean is that your query is sequentially full scanning all three tables, and you would like instead for it to use index scans.
Show the plan for the query. The predicate can be pushed down, but whether it makes any difference may depend:
- statistics on each table (full scan may be faster than index scan)
- are the various column1 columns indexed
- certain documented or hidden optimiser parameters can encourage or discourage push down: eg optimizercost_based_transformation
- Oracle version: there have been known bugs that interfere with push down (eg Bug 3723007 - Predicate push down may not occur in 10g - reported in 10.1)
HTH
Regards Nigel