两个查询，来自 sql 的两个结果试图在 php 中划分它们答案

【问题标题】：Two query, two results from sql trying to divide them in php两个查询，来自 sql 的两个结果试图在 php 中划分它们
【发布时间】：2013-05-17 15:01:45
【问题描述】：

我有两个来自 sql 的计数查询。我想划分这两个查询的结果。我试过了：

    $con = mysqli_connect("localhost", "root", "", "xoxo") or die(mysqli_connect_error());

    $query = "SELECT COUNT(xxxx) AS a zzzz";

    $query1 = "SELECT COUNT(xxxx) AS b FROM zzzz WHERE xxxx = 'cccc'";


    $result = mysqli_query($con, $query) or die('Error querying database');
    $result1 = mysqli_query($con, $query1) or die('Error querying database');

    $row = mysqli_fetch_array($result);
    $rowa = mysqli_fetch_array($result1);

    $x = $row/$rowa;

    echo $x;

但它告诉我它有一个致命错误。我也试过：

$con = mysqli_connect("localhost", "root", "", "xoxo") 或 die(mysqli_connect_error());

    $query = "SELECT COUNT(xxxx) AS row1 FROM zzzz";

    $query1 = "SELECT COUNT(xxxx) AS row2 FROM zzzz WHERE xxxx = 'cccc'";

    $result = mysqli_query($con, $query) or die('Error querying database');
    $result1 = mysqli_query($con, $query1) or die('Error querying database');


    while ($row = mysqli_fetch_array($result)) {

    }

    while ($row1 = mysqli_fetch_array($result1)) {

    }

    echo (int)($row['row1'] / $row1['row2']);

但它告诉我这是除以零。但是，我的 row1 和 row2 都对它有价值。

【问题讨论】：

$row 仅在 while 循环内可见，与 $row1 相同。

标签： php mysql division

【解决方案1】：

你已经在while loop中初始化了两个查询的结果

试试这个

 $row = mysqli_fetch_array($result);
 $row1 = mysqli_fetch_array($result1);

echo (int)($row['row1'] / $row1['row2']);

【讨论】：

【解决方案2】：

当您使用while 循环时，这意味着它将循环直到条件为假，这意味着您的$row 和$row1 都是假的。你需要的是：

$query = "SELECT COUNT(xxxx) AS row1 FROM zzzz";

$query1 = "SELECT COUNT(xxxx) AS row2 FROM zzzz WHERE xxxx = 'cccc'";

$result = mysqli_query($con, $query) or die('Error querying database');
$result1 = mysqli_query($con, $query1) or die('Error querying database');

$row = mysqli_fetch_array($result);
$row1 = mysqli_fetch_array($result1);

echo (int)($row['row1'] / $row1['row2']);

您的第一个示例不起作用，因为当您执行 $row/$rowa 时，您正在尝试划分 2 个数组...

【讨论】：

记得处理 $row1['row2'] == 0 这会导致 PHP 错误。