CREATE TABLE temp(
id text,
name text);

CREATE TABLE temp_counter(
temp integer);

CREATE FUNCTION temp_counter() RETURNS OPAQUE AS '
DECLARE
counters integer;
BEGIN
SELECT INTO counters COUNT(*) FROM TG_ARGV[0];
UPDATE temp_counter SET TG_ARGV[0] = counters;
END;
' LANGUAGE 'plpgsql';

CREATE TRIGGER temp_trigger
AFTER INSERT OR DELETE
ON temp
FOR EACH ROW
EXECUTE PROCEDURE temp_counter('temp');

INSERT INTO temp VALUES ('hoge','moga');
とすると
WARNING: Error occurred while executing PL/pgSQL function temp_counter
WARNING: line 4 at select into variables
ERROR: parser: parse error at or near "$1" at character 24
というエラーが出てしまうんですが。。なんでですか？
質問ばっかですみません。