Php Order by和group by mysql不工作

这就是我想要的

数据库

id | fromm | ontvanger | date | msg | gelezen
--------------------------------------------------
1  | kees  | marc     | time_stamp  | 0
1  | hans  | marc     | time_stamp  | 1
3  | kees  | marc     | time_stamp  | 0
5  | selma | marc     | time_stamp  | 1
6  | kees  | marc     | time_stamp  | 0
7  | kees  | marc     | time_stamp  | 0

这是我想要的弗洛姆的小组

1  | hans  | marc     | time_stamp  | 1
3  | kees  | marc     | time_stamp  | 0
5  | selma | marc     | time_stamp  | 1

$result = mysql_query("SELECT * FROM berichten where ontvanger = '$session->username' 
GROUP BY fromm ORDER BY date DESC
");

显示最新记录，gelezen首先为0

SELECT  a.*
FROM    berichten  a
        INNER JOIN
        (
            SELECT  fromm, MAX(date) date
            FROM    berichten
            GROUP   BY fromm
        ) b ON  a.fromm = b.fromm AND
                a.date = b.date
WHERE   a.ontvanger = '$session->username'
ORDER   BY (gelezen = 0) DESC, id

子查询允许您为每个

fromm

获取最新的

日期。然后将其结果连接回原始表，以获取列的其他值

（gelezen=0）
产生一个布尔值，如果该值为真，将给出
1
，否则
0
。由于要根据
gelezen=0
对行进行排序，请对布尔运算的结果应用降序。
Umm post所需的结果。结果中显示了hans kees和selma的第一篇文章。我想要最新的唱片