Question

我有一个客户，我正在开发一个视频网站。他希望从数据库中提取2个视频，以显示前端用户的投票结果。

视频表有一个“投票”字段。他希望随机提取视频，但对具有更高投票数的视频给予更高的偏好。某种算法，其中投票给予优先权，但不仅仅是直接“最高投票的2个视频被拉动”。

有什么想法吗？

看看我的视频表是什么样的：

$data[] = array(
        'id' => $row->id,
        'filename' => $row->filename,
        'added' => $row->added,
        'userId' => $row->userId,
        'contestId' => $row->contestId,
        'complete' => $row->complete,
        'ended' => $row->ended,
        'votes' => $row->votes
    );

Answer 1

只需使用一个很好的平衡的ORDER BY votes * ($offset + rand()) DESC和，其中偏移平衡随机化。如果offset为0，则它大部分是随机的，如果offset为1或更高，则不会显示未投票的视频。

您可以在干跑中尝试几次拍摄的视频，看看是否喜欢它。 ; - ）

编辑：

答案取决于数据库中的投票范围和分布。

Answer 2

考虑以下内容......

SELECT * FROM weighted;
+----+--------+
| id | weight |
+----+--------+
|  1 |      3 |
|  2 |      1 |
|  3 |      6 |
|  4 |      5 |
|  5 |     10 |
|  6 |      2 |
|  7 |      3 |
|  8 |      7 |
|  9 |      7 |
+----+--------+

So, crudely...

SELECT *,RAND()*weight FROM weighted;
+----+--------+--------------------+
| id | weight | RAND()*weight      |
+----+--------+--------------------+
|  1 |      3 | 1.7466305203238788 |
|  2 |      1 | 0.6615251914239724 |
|  3 |      6 | 3.3659728051777673 |
|  4 |      5 |  4.102008970549338 |
|  5 |     10 |  4.190225986940997 |
|  6 |      2 | 1.2678152837490806 |
|  7 |      3 |  2.737411332072142 |
|  8 |      7 |  4.624405276611824 |
|  9 |      7 | 3.9601472736896457 |
+----+--------+--------------------+

SELECT *,RAND()*weight x FROM weighted ORDER BY x DESC LIMIT 1;
+----+--------+--------------------+
| id | weight | x                  |
+----+--------+--------------------+
|  8 |      7 | 4.6799722441285585 |
+----+--------+--------------------+

SELECT *,RAND()*weight x FROM weighted ORDER BY x DESC LIMIT 1;
+----+--------+-------------------+
| id | weight | x                 |
+----+--------+-------------------+
|  9 |      7 | 5.331623214605845 |
+----+--------+-------------------+

SELECT *,RAND()*weight x FROM weighted ORDER BY x DESC LIMIT 1;
+----+--------+-------------------+
| id | weight | x                 |
+----+--------+-------------------+
|  4 |      5 | 4.931961209449881 |
+----+--------+-------------------+

SELECT *,RAND()*weight x FROM weighted ORDER BY x DESC LIMIT 1;
+----+--------+-------------------+
| id | weight | x                 |
+----+--------+-------------------+
|  8 |      7 | 6.230309537826394 |
+----+--------+-------------------+

SELECT *,RAND()*weight x FROM weighted ORDER BY x DESC LIMIT 1;
+----+--------+-------------------+
| id | weight | x                 |
+----+--------+-------------------+
|  5 |     10 | 5.470934962361059 |
+----+--------+-------------------+

从数据库中提取记录，优先选择具有较高投票数的记录

2 个答案: