我如何在php [duplicate]中按降序排序id和sub_id

Possible Duplicate:
How can I sort id and sub_id in descending order?

可能重复:如何按降序对id和sub_id进行排序?

I have a mysql table named gallery .

我有一个名为gallery的mysql表。

id    sub_id    name
1       10      jack
2       10      jack
3       11      rom
4       11      rom
5       12       win
6       12       win
7       13      shivam
8       13      shivam

There are 4 different sub_id but all have different id. So i just want to fetch only one id from every sub_id in descending order like below :

有4个不同的sub_id但都有不同的id。所以我只想从每个sub_id中获取一个id,降序如下:

id     sub_id      name
8        13        shivam
6        12        win
4        11         rom
2        10        jack

I used this query but it doesn't help me .

我使用了这个查询,但它对我没有帮助。

$sql="SELECT MAX(id), sub_id, name FROM gallery GROUP BY sub_id ORDER BY id DESC LIMIT 4";

2 个解决方案

#1

you may try by the following query

您可以尝试以下查询

$sql="SELECT MAX(id), sub_id, sub_name FROM gallery GROUP BY sub_id ORDER BY id DESC LIMIT 4";

#2

You should select the max "sub_id" of every group to obtain the desired result, and if the "id" is already ordered you needn't to put an order statement. So the query must look like this:

您应该选择每个组的最大“sub_id”以获得所需的结果,如果已经订购了“id”,则无需输入订单声明。所以查询必须如下所示:

SELECT MAX(  `id` ) ,  `sub_id` ,  `name` 
FROM  `gallary` 
GROUP BY  `sub_id`

for the limit you can add it easily. I hope that it helps.

对于限制,您可以轻松添加它。我希望它有所帮助。

#1