来自php中mysql的sum值

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

// 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);
}

// 查询数据库中的 SUM 值
$sql = "SELECT SUM(column_name) FROM table_name";
$result = $conn->query($sql);

// 输出结果
if ($result->num_rows > 0) {
  // 输出数据
  while($row = $result->fetch_assoc()) {
    echo "SUM 值: " . $row["SUM(column_name)"];
  }
} else {
  echo "0 结果";
}

// 关闭连接
$conn->close();
?>