php mysql变量赋值

<?php
// 创建数据库连接
$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);
}

// 使用SET语句为变量赋值
$sql = "SET @my_var = 'Hello, World!'";
if ($conn->query($sql) === TRUE) {
    echo "变量赋值成功";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

// 使用SELECT ... INTO语句为变量赋值
$sql = "SELECT column_name INTO @my_var FROM table_name WHERE condition";
$result = $conn->query($sql);

if ($result) {
    // 获取变量的值
    $var_value = $conn->query("SELECT @my_var")->fetch_assoc()['@my_var'];
    echo "变量值: " . $var_value;
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

// 关闭连接
$conn->close();
?>