Re: SQL Tunning

What you could do is create a concatenated index on address_id and any other small column in the same table. You could even add a dummy column with a default value of 'x'.

The NULL, 'x' combinations are included in b-tree indexes.

I tried this out sometime ago and it works.

This is better than creating a dummy value like -1 or so because that affects the functionality of the software.

"Christopher M. Day" wrote:
>
> Roman,
>
> Sybrand, Andrew and Serge are right about b-tree indexes, but is the
> column a candidate for a bitmap index, which will store null values.
>
> Chris.
>
> Roman Gelfand wrote:
> >
> > Consider the following statement.
> >
> > select first_name, last_name from table_adress where address_id is null;
> >
> > Eventhough address_id is indexed uniquely, there is a full table scan. Is
> > there a way to force index use without changing the sql statement?
> >
> > Thanks in advance
> > Roman
Received on Mon Mar 22 1999 - 01:58:23 CST