> LIKE operator is able to use index only if the pattern does
> not start with wildcard:
> myfield LIKE 'abc%'
> If you have command that has its pattern as parameter
> myfield LIKE ?
> than during prepare of such command FB has no idea what
> the actual value will be when executing it (whether is will
> start with wildcard
> or not), hence the plan can't use index.
>

Finally the engine does see the parameter too.
Hopefully Firebird 2.x will have another optimization stage to get along this pitfall.
We haven't had these performance problems with the sybase engine.
One problem with using STARTING WITH is that this isn't standard SQL. And thats important to us.

Guenther