php搜索数据库

<?php
$host = 'localhost';
$dbname = 'mydatabase';
$user = 'myuser';
$pass = 'mypassword';

try {
    $pdo = new PDO("mysql:host=$host;dbname=$dbname;charset=utf8", $user, $pass);
    
    // 预处理语句
    $stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username");
    $stmt->bindParam(':username', $username);
    
    // 设置参数并执行查询
    $username = 'john_doe';
    $stmt->execute();
    
    // 获取结果
    $result = $stmt->fetchAll(PDO::FETCH_ASSOC);
    
    foreach ($result as $row) {
        echo "ID: " . $row['id'] . " - Username: " . $row['username'] . "<br>";
    }
} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();
}
?>

$stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username");
$stmt->bindParam(':username', $username);

try {
    $pdo = new PDO("mysql:host=$host;dbname=$dbname;charset=utf8", $user, $pass);
} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();
}

CREATE INDEX idx_username ON users(username);