ORDER BY datetime

Question

ORDER BY datetime DESC

将这些作为我的结果给我

2016-02-24 12:45:00
2016-02-20 18:00:00
2016-02-22 16:00:00

这对我来说没有意义，它怎么能这样排序？我的数据库结构将列设置为＆＃34; DATETIME＆＃34;所以我不知道这是否影响了它，但我如何按日期和时间订购时间？

编辑＃1：

SELECT teams.t_id, teams.t_name, t.t_id AS t_id2, t.t_name AS t_name2, matches.m_id, matches.m_datetime, divisions.d_id, divisions.d_name, leagues.l_id, leagues.l_name 
        FROM matches 
            LEFT JOIN teams ON teams.t_id = matches.m_tid
            LEFT JOIN teams t ON t.t_id = matches.m_tid2 
            LEFT JOIN divisions ON divisions.d_id = matches.m_did
            LEFT JOIN leagues ON leagues.l_id = divisions.d_lid
        WHERE leagues.l_id = ?
        ORDER BY matches.m_datetime DESC, matches.m_id DESC

查询有效，但由于某种原因它没有排序。