PHP MySQL 读取数据

从 MySQL 数据库读取数据

SELECT 语句用于从数据表中读取数据:

SELECT column_name(s) FROM table_name

如需学习更多关于 SQL 的知识，请访问我们的 SQL 教程。

以下实例中我们从表 MyGuests 读取了 id, firstname 和 lastname 列的数据并显示在页面上：

实例 (MySQLi - 面向对象)

<?php  
$servername = "localhost";  
$username = "username";  
$password = "password";  
$dbname = "myDB";  

// 创建连接  
$conn = new mysqli($servername, $username, $password, $dbname);  
// 检测连接  
if ($conn->connect_error) {  
    die("Connection failed: " . $conn->connect_error);  
}  

$sql = "SELECT id, firstname, lastname FROM MyGuests";  
$result = $conn->query($sql);  

if ($result->num_rows > 0) {  
    // 输出每行数据  
    while($row = $result->fetch_assoc()) {  
        echo "<br> id: ". $row["id"]. " - Name: ". $row["firstname"]. " " . $row["lastname"];  
    }  
} else {  
    echo "0 results";  
}  
$conn->close();  
?>

以下实例读取了 MyGuests 表的所有记录并显示在 HTML 表格中：

实例 (PDO)

<?php  
echo "<table style="border: solid 1px black;">";  
echo "<tr><th>Id</th><th>Firstname</th><th>Lastname</th><th>Email</th><th>Reg date</th></tr>";  

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>" . "
";  
    }  
}  

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

try {  
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);  
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);  
    $stmt = $conn->prepare("SELECT * FROM MyGuests");  
    $stmt->execute();  

    // 设置结果集为关联数组  
    $result = $stmt->setFetchMode(PDO::FETCH_ASSOC);  

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