Error in plpgsql function: array value must start with "{" or dimension information - function

Question

I'm trying to format the results of this query:
CREATE OR REPLACE FUNCTION "alarmEventList"(sampleid integer
, starttime timestamp without time zone
, stoptime timestamp without time zone)
RETURNS text[] AS
$BODY$DECLARE
result text[];
BEGIN
select into result array_agg(res::text)
from (
select to_char("Timestamp", 'YYYY-MM-DD HH24:MI:SS')
,"AlertLevel"
,"Timestamp" - lag("Timestamp") over (order by "Timestamp")
from "Judgements"
WHERE "SampleID" = sampleid
and "Timestamp" >= starttime
and "Timestamp" <= stoptime
) res
where "AlertLevel" > 0;
select into result array_to_string(result,',');
return result;
END
$BODY$
LANGUAGE plpgsql VOLATILE
Right now without array_to_string() I get something like this:
{"(\"2013-10-16 15:10:40\",1,00:00:00)","(\"2013-10-16 15:11:52\",1,00:00:48)"}
and I want something like this:
2013-10-16 15:10:40,1,00:00:00 | 2013-10-16 15:11:52,1,00:00:48 |
But when I run the query I get error:
array value must start with "{" or dimension information

Answer 1

You do not actually want an array type, but a string representation.
Can be achieved like this:
CREATE OR REPLACE FUNCTION "alarmEventList"(sampleid integer
, starttime timestamp
, stoptime timestamp
, OUT result text) AS
$func$
BEGIN
SELECT INTO result string_agg(concat_ws(','
,to_char("Timestamp", 'YYYY-MM-DD HH24:MI:SS')
,"AlertLevel"
,"Timestamp" - ts_lag)
, ' | ')
FROM (
SELECT "Timestamp"
,"AlertLevel"
,lag("Timestamp") OVER (ORDER BY "Timestamp") AS ts_lag
FROM "Judgements"
WHERE "SampleID" = sampleid
AND "Timestamp" >= starttime
AND "Timestamp" <= stoptime
) res
WHERE "AlertLevel" > 0;
END
$func$ LANGUAGE plpgsql
The manual on string_agg() and concat_ws().