從mysql資料庫取一條記錄里的某個欄位的值

<?php

$link = mysqli_connect("localhost","root","root","dbname"); //連接資料庫

$sql = "select field from dbname  limit 1"; 

$ressql = mysqli_query($link,$sql);//執行sql

$res = $ressql->fetch_object()->field;//得到結果