Hi,

> I'm using FIREBIRD 1.5 and I have a question.
> What SQL has the best performance ?
>
> 1) select * from planoconta where nivel like '01.01%'
>
> or
>
> 2) select * from planoconta where substring(nivel from 1 for 5) =

'01.01'

If you have an index of NIVEL, the first one is the
fastest.

The second one cannot use an index.

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server.
Upscene Productions
http://www.upscene.com