[firebird-support] Evaluate "empty" string

[Jorge Andres Brugger jorge.brug...@gmail.com [firebird-support]]

Hello all.
I need to evaluate if one SP varchar parameter is "not empty". I´m using:
if (((CHAR_LENGTH(trim(terminal))>0) or (terminal is not null)) then <do
something>.
If I send '' (empty string) as parameter content, the expression evaluates
to true (I´m expecting to get a false).
What am I doing wrong?
Thanks!