如何在php mysql中查找相同值的行数

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

$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 构建SQL查询语句
$sql = "SELECT column_name, COUNT(*) as count
        FROM table_name
        GROUP BY column_name
        HAVING count > 1";

// 执行查询
$result = $conn->query($sql);

// 解析查询结果
if ($result->num_rows > 0) {
    while ($row = $result->fetch_assoc()) {
        $columnValue = $row["column_name"];
        $count = $row["count"];
        echo "字段值为 " . $columnValue . " 的行数为 " . $count . "<br>";
    }
} else {
    echo "没有找到相同值的行";
}

// 关闭数据库连接
$conn->close();
?>