<?php
$servername = "localhost";
$username = "root";
$password = "root";
$dbname = "test";
 
// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
} 
 
$sql = "SELECT * FROM master";
$result = $conn->query($sql);
//有结果 
if ($result->num_rows > 0) { 
    //返回数据总条数
    $data_count=$result->num_rows;
    //方案1 
    //循环次数
    $num=1;
    // while 输出数据
    while($row = $result->fetch_assoc()) { 
        //之前的次数
        if($num<$data_count){
            echo 'num:'.$num.'id='.$row['id'].'<br/>';
        }
        //当循环次数等于数据总是 就是最后一条数据
        if($data_count==$num){
            echo 'Last num;'.$num.'id='.$row['id'].'<br/>'; 
        }
        //累加循环次数
        $num++;
    }
     
} else {
    echo "0 结果";
}
$conn->close();
?>