数据库数据中拥有自己的计数器

Question

id | num | text
1  | a   | sdfsdf
2  | a   | sdfsdf
3  | b   | sdfsdf
4  | c   | sdfsdf
5  | a   | sdfsdf
6  | b   | sdfsdf
7  | a   | sdfsdf
8  | c   | sdfsdf

我在 num = a 和 orderBy ID DESC 处进行查询，我有：

id | num | text
7  | a   | sdfsdf
5  | a   | sdfsdf
2  | a   | sdfsdf
1  | a   | sdfsdf

我想为这个自己的计数器添加：

count | id | num | text
  4   | 7  | a   | sdfsdf
  3   | 5  | a   | sdfsdf
  2   | 2  | a   | sdfsdf
  1   | 1  | a   | sdfsdf

我使用 foreach PHP 获取数据：

foreach ($data as $i => $dat) {
   echo $dat->id . $dat->num . $dat->text;
}

我想要一些东西：

foreach ($data as $i => $dat) {
   echo $i . $dat->id . $dat->num . $dat->text;
}

但 $i 方向相反

Answer 1

你可以这样做：

$count = count($data);
foreach ($data as $i => $dat) {
   echo ($count - $i) . $dat->id . $dat->num . $dat->text;
}

Answer 2

在 PHP 中：

$i = count($data);
foreach ($data as $dat) {
    echo $i . $dat->id . $dat->num . $dat->text;
    $i--;
}

Answer 3

您知道，您可以在 SQL 查询中解决这个问题。这是针对生产 Redmine 数据库实例 (MySQL) 运行的示例：

select @curRow := @curRow + 1 AS row_number, issues.*
from issues, (SELECT @curRow := 0) r
where project_id = 7
and tracker_id = 3
order by 1 desc