php mysql首字母查询

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

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 获取用户输入的首字母
$letter = $_GET['letter'];

// 构建SQL查询语句
$sql = "SELECT * FROM myTable WHERE name LIKE '$letter%'";

// 执行查询
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()) {
        echo "ID: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
    }
} else {
    echo "0 结果";
}
$conn->close();
?>

$stmt = $conn->prepare("SELECT * FROM myTable WHERE name LIKE ?");
$stmt->bind_param("s", $letter . '%');
$stmt->execute();
$result = $stmt->get_result();

CREATE INDEX idx_name ON myTable (name);

if (!empty($letter) && ctype_alpha($letter)) {
    // 执行查询
}