Issue with plpgsql trigger - Mailing list pgsql-sql

I'm only learning this, but I've got a working function that I want to
be invoked in a trigger. The function itself is:


CREATE FUNCTION online_pct_func(integer, interval)
RETURNS boolean AS '

DECLARE
on numeric;off numeric;
o_pct numeric;
op varchar;

BEGIN
on := 0;off := 0;
SELECT count(info.online) INTO onFROM infoWHERE info.id = $1AND info.online = ''1''AND info.iso_date_time > (now() -
CAST($2AS interval));
 
SELECT count(info.online) INTO offFROM infoWHERE info.id = $1AND info.online = ''0''AND info.iso_date_time > (now() -
CAST($2AS interval));
 
o_pct := (on / (on + off)) * 100.0;
op := ''UPDATE online_pct '';
IF $2 = ''01:00'' THEN op := op || ''SET on1hr = '' || o_pct || '', isodt1hr = current_timestamp '';ELSIF $2 = ''1
day''THEN op := op || ''SET on1day = '' || o_pct || '', isodt1day = current_timestamp '';ELSIF $2 = ''1 week'' THEN op
:=op || ''SET on1wk = '' || o_pct || '', isodt1wk = current_timestamp '';ELSIF $2 = ''1 mon'' THEN op := op || ''SET
on1mo= '' || o_pct || '', isodt1mo = current_timestamp '';ELSIF $2 = ''1 year'' THEN op := op || ''SET on1yr = '' ||
o_pct|| '', isodt1yr = current_timestamp '';END IF;
 
op := op || ''WHERE id = '' || $1;
EXECUTE op;
RETURN 1;

END;

' LANGUAGE 'plpgsql';


It gives the intended outcome by itself, for example with select
online_pct_func(1, '1 year');

The trigger I've got, which is not working for me, is as follows: 


CREATE FUNCTION online_pct_trig() RETURNS opaque AS '

DECLARE
i1hr     timestamp;i1day     timestamp;i1wk     timestamp;i1mo     timestamp;i1yr     timestamp;
oper     varchar;

BEGIN
SELECT     o.isodt1hr INTO i1hr,    o.isodt1day INTO i1day,    o.isodt1wk INTO i1wk,    o.isodt1mo INTO i1mo,
o.isodt1yrINTO i1yrFROM online_pct oWHERE o.id = NEW.id;
 
oper := ''SELECT online_pct_func(NEW.id, '';
IF i1hr <= (now() - ''00:01''::interval) THEN oper := oper || ''01:00'' || '');'';EXECUTE oper;END IF;IF i1day < (now()
-''01:00''::interval)THEN oper := oper || ''1 day'' || '');'';EXECUTE oper;END IF;IF i1wk < (now() = ''1
day''::interval)THENoper := oper || ''1 week'' || '');'';EXECUTE oper;END IF;IF i1mo < (now() - ''1
week''::interval)THENoper := oper || ''1 mon'' || '');'';EXECUTE oper;END IF;IF il1yr < (now() - ''1
mon''::interval)THENoper := oper || ''1 year'' || '');'';EXECUTE oper;END IF;
 
RETURN NEW;

END;

' LANGUAGE 'plpgsql';

CREATE TRIGGER online_pct_trig
AFTER INSERT ON info
FOR EACH ROW EXECUTE PROCEDURE online_pct_trig();


I'm guessing there's an obvious error in there that I can't identify;
but I've gotten nowhere with it on my own. I guess I'm looking for any
input on this..

- Oeln