如何在phpmysql中知道mysql数据库中每一行的最大数量，并返回列名或返回名

<?php
// 连接到MySQL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, $dbname);
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 查询每个表中每一行的最大数量
$sql = "SELECT TABLE_NAME, COLUMN_NAME, MAX_ROW_COUNT
        FROM (
            SELECT TABLE_NAME, COLUMN_NAME, COUNT(*) AS MAX_ROW_COUNT
            FROM INFORMATION_SCHEMA.COLUMNS
            WHERE TABLE_SCHEMA = '$dbname'
            GROUP BY TABLE_NAME, COLUMN_NAME
        ) AS subquery
        ORDER BY MAX_ROW_COUNT DESC";

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

if ($result->num_rows > 0) {
    // 输出结果
    while($row = $result->fetch_assoc()) {
        echo "表名: " . $row["TABLE_NAME"]. " - 列名: " . $row["COLUMN_NAME"]. " - 最大数量: " . $row["MAX_ROW_COUNT"]. "<br>";
    }
} else {
    echo "没有找到任何数据";
}

$conn->close();
?>