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