php筛选查询

<?php
// 数据库连接信息
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 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);
}

// 获取用户输入的筛选条件
$name = $_GET['name'] ?? '';
$age = $_GET['age'] ?? '';

// 构建SQL查询语句
$sql = "SELECT * FROM users";
$conditions = [];

if (!empty($name)) {
    $conditions[] = "name LIKE '%$name%'";
}
if (!empty($age)) {
    $conditions[] = "age = $age";
}

if (!empty($conditions)) {
    $sql .= " WHERE " . implode(' AND ', $conditions);
}

// 执行查询
$result = $conn->query($sql);

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

// 关闭连接
$conn->close();
?>

$stmt = $conn->prepare("SELECT * FROM users WHERE name = ?");
$stmt->bind_param("s", $name);
$stmt->execute();
$result = $stmt->get_result();

CREATE INDEX idx_name ON users(name);

if (!$result) {
    die("查询失败: " . $conn->error);
}