> Hello,
>
> If I select some fields from mytable with ,where field = XX' or ,where field
> > XX', the indexed fields were read indexed (displayed from IBExpert). But
> If I select some fileds from mytable with 'where field is distinct from XX',
> the read is not indexed.
>
> It is already okay?

Hi Olaf!

You cannot compare IS DISTINCT FROM with equality or greater than, rather, IS DISTINCT FROM is comparable to difference. Hence, I'd say

field IS DISTINCT FROM XX
is similar to
field <> XX

and that

field = XX
is similar to
field IS NOT DISTINCT FROM XX

So, is the read indexed if you try

WHERE field IS NOT DISTINCT FROM XX?

Set