CREATE FUNCTION reorder_priority() RETURNS TRIGGER AS $$
BEGIN
CASE TG_OP
WHEN 'UPDATE' THEN
UPDATE
link
SET
priority = priority + 1
WHERE
link.priority >= NEW.priority AND
NOT link.priority > OLD.priority;
END CASE;
RETURN NULL;
END;
$$ LANGUAGE plpgsql;正确解法
BEGIN
CASE TG_OP
WHEN 'UPDATE' THEN
UPDATE
link
SET
priority = priority + 1
WHERE
link.priority >= NEW.priority AND
NOT link.priority >= OLD.priority;
END CASE;
RETURN NEW;
END;