Richard,
> But only if 'sometable.csv' exists;
>
> If 'sometable.csv' does not exist as an input table I want to continue
> the next command.
Sorry, can't be done in plpgsql. Regular procedural languages are
deliberately kept ignorant of the host filesystem in order to prevent
database users from being able to compromise it. It's a security thing.
You could easily write a function in an "untrusted" language, like PL/PerlU or
PL/PythonU, which would test for file existence and return a true/false
value.
--
Josh Berkus
Aglio Database Solutions
San Francisco