如何使用PHP客户端库获取最近30天内每天的会话计数

<?php
// 连接数据库
$servername = "数据库服务器地址";
$username = "数据库用户名";
$password = "数据库密码";
$dbname = "数据库名";

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

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

// 查询最近30天内每天的会话计数
$query = "SELECT DATE(session_start_time) AS session_date, COUNT(*) AS session_count FROM sessions WHERE session_start_time >= DATE_SUB(NOW(), INTERVAL 30 DAY) GROUP BY DATE(session_start_time)";

$result = $conn->query($query);

if ($result->num_rows > 0) {
    // 输出每天的会话计数
    while ($row = $result->fetch_assoc()) {
        echo "日期：" . $row['session_date'] . "，会话计数：" . $row['session_count'] . "<br>";
    }
} else {
    echo "没有找到会话数据";
}

// 关闭数据库连接
$conn->close();
?>