Fwd: Re: question - plpgsql and query on table given by variable

Thank you for your reply. It helped me, but I need know some results. So I tryed use SELECT INTO in EXECUTE string and
itdo not work. Also I try this: 

CREATE OR REPLACE FUNCTION n(varchar) RETURNS varchar AS $$
DECLARE
 a varchar;
BEGIN
 a := $1;
 PERFORM * FROM b;
 EXECUTE 'PERFORM AsText(the_geom) FROM ' || a || ';';
 IF FOUND THEN
 RETURN 'yes';
 END IF;
 IF FOUND THEN
 RETURN 'no';
 END IF;
 RETURN 'I do not know';
END;
$$ LANGUAGE plpgsql;

Error:
SELECT n('b');
ERROR: syntax error at or near "PERFORM" at character 1
QUERY: PERFORM AsText(the_geom) FROM b;
CONTEXT: PL/pgSQL function "n" line 7 at execute statement
LINE 1: PERFORM AsText(the_geom) FROM b;

When I use PPERFORM in normal way, it works. How I can reach some results from the query executed by EXECUTE?

Thanks for your help