mysql - 按降序选择唯一行

Question

我想按时间 DESC 选择每个 id 顺序插入的最后一行

s.no     id    message           status     time
1        3     this is msg 1     unread     100001
2        2     this is msg 2     read       100002
3        4     this is msg 3     read       100003
4        3     this is msg 4     unread     100004
5        2     this is msg 5     read       100005
6        3     this is msg 6     unread     100006

我在用

select * from table group by id order by MAX(time) DESC

它给出了正确的id顺序，但行互换

了我希望它像：

s.no     id    message           status     time
6        3     this is msg 6     unread     100006
5        2     this is msg 5     read       100005
3        4     this is msg 3     read       100003

请帮帮我

Answer 1

您可以将最大时间作为单独的子查询提取出来，然后将其重新连接到表中。如果 id 有重复的最大时间，这将返回多行。

select 
    t.s.no,
    t.id
    t.message,
    t.status,
    t.time
from 
    table t
        inner join (
        select
            id,
            max(time) maxtime
        from
            table
        group by
            id
   ) mt
       on mt.id = t.id and t.time = mt.maxtime
order by
    t.time desc

Answer 2

尝试这个：

select * from `table` t
join (
  SELECT id, MAX(`time`) max_t
  FROM `table`
  GROUP BY id
  ) m
on (t.id=m.id and t.`time`=m.max_t)
order by m.max_t desc