Question

我做了这个查询，向我展示了排名＆＃39;按点排序的结果。查询工作正常但由于某种原因，我没有得到任何结果，试图用PHP获取它也许有人可以告诉我为什么？

(int) $a    = $_GET['a'];
if($ranking = $con->prepare("SET @rownum := 0; SELECT rank, id FROM (SELECT @rownum := @rownum + 1 AS rank, id FROM anime ORDER BY points DESC) as result WHERE id=$a"))
{
    $ranking->execute();
    $ranking->next_result();
    $ranking->bind_result($rank, $id);

    while($ranking->fetch()) 
    {
        var_dump($rank, $id);
        if($id == $a)
        {
          echo "<span class='rnknr'>#$rank</span>";
        }
    }

    $ranking->close();
}

}

Answer 1

$ ranking-＆GT;执行（）;如果查询包含多个表达式，则可能返回多个结果集。

Answer 2

试试这个

(int) $a    = $_GET['a'];
if($ranking = $con->prepare("SET @rownum := 0; SELECT rank, id FROM (SELECT @rownum := @rownum + 1 AS rank, id FROM anime ORDER BY points DESC) as result WHERE id=1"))
{
    $ranking->execute();
    $ranking->next_result(); //<- advance to the result set for 2nd query (The select query)
    $ranking->bind_result($rank, $id);

    while($ranking->fetch()) 
    {
    if($id == $a)
        {
          echo "<span class='rnknr'>#$rank</span>";
        }
    }

    $ranking->close();
}

您的语句中有2个查询，因此只有调用fetch才会显示第一个查询SET @rownum := 0的结果。您需要通过调用next_result

前进到第二个结果集

Answer 3

你必须使用mysqli::multi_query中的一些特殊方法，因为这是多查询:)现在你的代码看起来像这样：


$mysqli = mysqli_connect(HOST, USER, PASS, DB);

#(int) $a = $_GET['a']; -> What is this ?

$a = (int)$_GET['a']; //This is simplest casting

$sql = 'SET @rownum := 0; SELECT rank, id FROM (SELECT @rownum := @rownum + 1 AS rank, id FROM anime ORDER BY points DESC) as result WHERE id='.$a;
if ($mysqli->multi_query($sql)) {
    $mysqli->next_result();
    $result = $mysqli->store_result();
    while ($row = $result->fetch_assoc()) {
        if($row['id'] == $a)
        {
          echo "rank: #{$row['rank']}";
        }
    }
}

查询不会保存

3 个答案: