MySQL RAND() 不工作，总是得到相同的结果 [英] MySQL RAND() not working, always getting same result

问题描述

我有这个 MySQL 查询:

I have this MySQL query :

while ($x <= 9) {
   $data_1 = "SELECT scene FROM star WHERE star LIKE '%".$star."%' ORDER BY RAND() LIMIT  1";
   $result_1 = mysql_query ($data_1) OR die("Error: $data_1 </br>".mysql_error());

   while($row_1 = mysql_fetch_object($result_1)) {
      $scene = $row_1->scene;
      $x = $x + 1;
   }
} 

我想每次执行都得到一个新场景，但我总是得到相同的场景.这是什么问题?有人可以给我指点我必须搜索的方向吗?

I want to get everytime a new scene for each execution, but I always get the same scene. Whats the issue? Can someone make me a few pointers in which direction I have to search ?

推荐答案

您需要做的是将随机种子绑定到每一行，并且每次都绑定一个新种子.为此，请为您的表分配一个随机值作为别名临时列，然后然后从中选择.

What you need to do is tie a random seed to each row, and tie a new one each time. Do this by assigning a random value as an aliased transient column to your table, and then select from it.

SELECT s.scene as scene FROM (
    SELECT stars.scene as scene, RAND() as seed 
      FROM stars
     WHERE star LIKE '%".$star."%' 
  ORDER BY seed
) s
LIMIT  1;

使用 PDO 看起来像这样:

Using PDO it's going to look something like this:

function getScene() {
    $sql = 'SELECT s.scene as scene FROM ( SELECT stars.scene as scene, RAND() as seed FROM stars WHERE star LIKE '%:star%' ORDER BY seed ) s LIMIT  1;';
    $query = $this->db->prepare($sql);//'db' is the PDO connection
    $query->execute(array(':star' => "Allison Brie"));

    foreach ($conn->query($sql) as $row) {
        print $row['scene'] . "\t";
    }
}

我不确定你想用其余代码完成什么，但它大多看起来很笨拙.

I'm not sure what you were trying to accomplish with the rest of your code, but it mostly looks like cruft.

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