PGSQL报警表去重取最新，但是描述字段不去重

SELECT dev_id, "desc", alert_time
FROM (
  SELECT dev_id, "desc", alert_time,
         ROW_NUMBER() OVER (PARTITION BY dev_id ORDER BY alert_time DESC) AS row_num
  FROM alarm
) AS subquery
WHERE row_num = 1;

--这是一种终极解决办法

比max(时间)  order by靠谱