oracle indexes

Hello,

Say If I have a table with column a, and column b (say they are integers).

Sometimes I will do a query with a where clause that just references column a.

Sometimes I will do a query with a where clause that references both column a and b.

Is there a need to create an index with a, and an index with a, b? Or will an index with a,b work for both of the above types of queries?

I know in mysql if I have an index (a, b, c), then it is useful for queries referencing a or a,b or a, b,c. But, I am not as familiar with how Oracle indexes work.

Thanks. Received on Wed Jun 04 2008 - 23:01:59 CDT