PHP::难以理解如何引用 mysql 选择数组中的特定行...？

Question

我只是没有在这里建立联系，我没有得到帮助我启发自己的搜索结果。

我正在从 mysql 中提取数据到一个数组中。但是我完全想念稍后如何引用特定行。

try {
$conn = new PDO('mysql:host=localhost;dbname=FermentorDB', $username, $password);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);



$chamberstate = $conn->query('SELECT * FROM ChamberState' . $conn->quote($mac));


foreach($chamberstate as $row) {
    $chamber = $row['Chamber'];
    $schedule = $row['Schedule'];
    $runningnow = $row['RunningNow'];
    $temp = $row['ChangingTemp'];
    $array = array($chamber,$schedule,$runningnow,$temp); 


    }


} catch(PDOException $e) {
echo 'ERROR: ' . $e->getMessage();

好的，所以所有数据都在数组中。但是，我该如何打印 $schedule where $chamber == 1 呢？

我因为没有得到这个而感到很愚蠢......

Answer 1

您接近原始代码，但每次循环时 $array 变量都被覆盖。如果您需要访问整个页面中的值，您应该能够使用这样的方法来实现。

<?php
    try {
        $conn = new PDO('mysql:host=localhost;dbname=FermentorDB', $username, $password);
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

        $chamberstate = $conn->query('SELECT * FROM ChamberState' . $conn->quote($mac));

        /* Populate this array for later use */
        $chambers=array();

        foreach( $chamberstate as $row ) {
            $chamber = $row['Chamber'];
            $schedule = $row['Schedule'];
            $runningnow = $row['RunningNow'];
            $temp = $row['ChangingTemp'];

            /* This will overwrite any values in the $array variable with each iteration through the loop */
            /*
                $array = array( $chamber, $schedule, $runningnow, $temp ); 
            */

            $chambers[]=array( 'chamber'=>$chamber, 'schedule'=>$schedule, 'running'=>$runningnow, 'temp'=>$temp );
        }


        /* later, when you need to access the various values, you can reference via the index */
        echo $chambers[ 1 ]['chamber'];

        /* or */
        echo $chambers[ 23 ]['schedule'];


    } catch(PDOException $e) {
        echo 'ERROR: ' . $e->getMessage();
    }
?>