Hi,
i need some help/advice from the big-hands people, regarding the
optimization of query and creation of Indexes.


I create one table,
eg:
CREATE TABLE TAB1
( a number, d date, c varchar2(1) );

CREATE INDEX tab1_idx on tab1(d,c);

If i put this codition in where clause

Select * from tab1 where d > sysdate and c is null;
-- Index is access for this query

if i used this query
select * from tabl where ( (d>sysdate and c is null) or ( d
is null and c is null ) ) ;
-- TABLE ACCESS FULL is performed.


what i did was
drop the existing index and create the Bitmap index like

CREATE BITMAP INDEX tab1_idx on tab1(d,c);
if i used this query
select * from tabl where d is null and c is null ;
-- index is accessed

but for this query
select * from tabl where ( (d>sysdate and c is null) or ( d
is null and c is null ) ) ;
******* the same full table is accessed.

How i have to solve this issue ( means, how i have to make the index
)

expect your reply for this.

Thanks,
Sekaran D.
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