NO DATA FOUND Exception

Hi.

Im taking my first steps with plpgsql.
I want my function to react to the result of a query in the following way:

begin select column into variable from table where condition;
exception when <<data_found>> then return variable; when <<no_data_found>> then <<do nothing/continue>> ; when
<<any_other_exception>>then <<raise some error message>> ;
 
end ;

Is something like this possible en plpgsql without recurring to a select
count(*) to check how many results I will get?


Actual code is:

CREATE OR REPLACE FUNCTION test(p_line text) RETURNS text AS
$body$
DECLARE v_len integer DEFAULT 8; v_search varchar; v_register num_geo%ROWTYPE;
BEGIN
 -- Search loop WHILE v_len > 0 LOOP   v_search := substring(p_line, 1, v_len);   begin     SELECT * INTO v_register
WHEREprefix = v_search;   exceptionwhen no_data then        -- Getting error here    continue;       when others then
return v_register.prefix;   end;       v_len := v_len - 1; END LOOP;
 
 raise 'Not found';
END;
$body$
LANGUAGE 'plpgsql' VOLATILE ;


ERROR: unrecognized exception condition "no_data"
SQL state: 42704
Context: compile of PL/pgSQL function "test" near line 14


Thanks,
Fernando.