PHP mysql查询不能使用多个"AND“运算符

<?php
// 连接到MySQL数据库
$servername = "localhost";
$username = "your_username";
$password = "your_password";
$dbname = "your_database";

$conn = new mysqli($servername, $username, $password, $dbname);

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

// 构建查询语句
$sql = "SELECT * FROM your_table WHERE column1 = 'value1' AND column2 = 'value2' AND column3 = 'value3'";

// 执行查询
$result = $conn->query($sql);

// 处理查询结果
if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        // 输出每一行数据
        echo "列1: " . $row["column1"]. " - 列2: " . $row["column2"]. " - 列3: " . $row["column3"]. "<br>";
    }
} else {
    echo "没有结果";
}

// 关闭数据库连接
$conn->close();
?>