sql - how to get current row value in plpgsql function -

i need create plpgsql methods use current row value without passing in parameter in update command.

i tried

create temp table test ( test text, result text ) on commit drop; insert test values ('1','');  create or replace function public.gettest() returns text $$ declare   comp text := null;  begin execute 'select ''current row '' ||test.test' comp; return comp; end; $$ language plpgsql strict stable;  update test set result = 'result: ' || gettest(); 

but got exception

error:  missing from-clause entry table "test" line 1: select 'current row ' ||test.test                                    ^ query:  select 'current row ' ||test.test context:  pl/pgsql function gettest() line 6 @ execute statement ********** error **********  error: missing from-clause entry table "test" sql state: 42p01 context: pl/pgsql function gettest() line 6 @ execute statement 

how fix ? how fix without passing vaue plpgsql method parameter ?

there no such thing "implicit current row". have pass the function whatever needs parameter. can pass complete row if want to:

create temp table test (val text, result text ) on commit drop; insert test values ('1',''); insert test values ('2','');  create or replace function gettest(p_test test) returns text $$ declare   comp text := null; begin    comp := 'current row '||p_test.val; return comp; end; $$ language plpgsql strict stable;  update test set result = 'result: ' || gettest(test); 

i had rename column test else, otherwise call gettest(test) refer column not whole table (=row) , didn't work.