PHP/MYSql PDO 选择变量

Question

编辑: 好吧，当我将它设置为 28 时，虽然这对 $ID 非常有效，但它不适用于下面的实例，如果我试图获取 $name = $TableRows['name']; 变量。我知道我可以选择它，但其他变量需要这个。

$ID = 28; 
$name = $TableRows['name']; 

try { ini_set('display_errors', true); 
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password); $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
$stmt = $conn->prepare(" SELECT ? AS name FROM TABLE1 e WHERE id = ?"); 
$stmt->execute(array($name, $ID));
$result = $stmt->setFetchMode(PDO::FETCH_ASSOC); 

foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k=>$v) {
    echo $v;
}
}

我正在从 MySQLi 过渡到 PDO。我的问题是我想修改我的 SELECT 查询中的一个值，类似于我将 ID 的 WHERE 值设置为 $ID = 28 。有谁知道如何不只是从 SELECT 查询中输出 millisecondstime，而是可以将其更改为输出 $minutes $secondsrounded $millisecondsround？这就是我想要的想法:

$stmt = $conn->prepare("SELECT name, $minutes, $secondsrounded, $millisecondsround FROM TABLE1 e

这是我的整个查询:

<?php
echo "<center><div style='max-width: 1100px'><table id ='myTable' class='display' cellspacing='0' width='100%'>
    <thead>
    ";
echo "<tr><th>Name</th><th>Time</th></tr></thead>";

class TableRows extends RecursiveIteratorIterator { 
    function __construct($it) { 
        parent::__construct($it, self::LEAVES_ONLY); 
    }

    function current() {
        return "<td style='width: 150px; border: 1px solid black;'>" . parent::current(). "</td>";
    }

    function beginChildren() { 
        echo "<tr>"; 
    } 

    function endChildren() { 
        echo "</tr>" . "\n";
    } 
} 

$servername = "localhost";
$username = "";
$password = "";
$dbname = "";

$name = $TableRows['name'];

$milliseconds = $TableRows['millisecondstime'];

$time = $milliseconds / 1000;
$days = floor($time / (24*60*60));
$hours = floor(($time - ($days*24*60*60)) / (60*60));
$minutes = floor(($time - ($days*24*60*60)-($hours*60*60)) / 60);
$seconds = ($time - ($days*24*60*60) - ($hours*60*60) - ($minutes*60)) % 60;

$str_length = 3;
$millisecondsround = substr("000{$milliseconds}", -$str_length);
$secondsrounded = str_pad($seconds, 2, '0', STR_PAD_LEFT);

$ID = 28;   

try {
    ini_set('display_errors', true);
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $stmt = $conn->prepare("SELECT name, millisecondstime FROM TABLE1 e 
        WHERE ID = ?
        ORDER BY millisecondstime ASC
        "); 

    $stmt->execute(array($ID));
    $result = $stmt->setFetchMode(PDO::FETCH_ASSOC); 
    foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k=>$v) {
        echo $v;
    }
}
catch(PDOException $e) {
    echo "Error: " . $e->getMessage();
}
$conn = null;
echo "</table>";
?> 

Answer 1

您可以在 SELECT 列表中使用占位符，它们将被替换为参数数组中的值。

$stmt = $conn->prepare("
    SELECT name, ? AS minutes, ? AS secondsrounded, ? AS millisecondsround 
    FROM TABLE1 e 
    WHERE id = ?");
$stmt->execute(array($minutes, $secondsrounded, $millisecondsround, $ID));