CREATE OR REPLACE FUNCTION division_string (text)  RETURNS text AS ' 
DECLARE 
            source_string ALIAS  FOR $1; 
            a (text);
            b (text);
BEGIN  
	a := substr(source_string, 0, 11); 
             b := substr(source_string, 11, 9);
            RETURN a ''/''  b;
            
END; 
' 
LANGUAGE 'plpgsql' 

test=# select division_string('PostgreSQL is cool');
NOTICE:  plpgsql: ERROR during compile of division_string near line  4 
ERROR:  parser: parse error at near  "(" 
test=#