php 多条件查询

class Page {
   private $total;                   //数据表中总记录数
   private $listRows;                    //每页显示行数
   private $limit;                   //SQL语句使用limit从句,限制获取记录个数
   private $uri;                     //自动获取url的请求地址
   private $pageNum;                 //总页数
   private $page;                   //当前页  
   private $config = array(
         'head' => "条记录", 
         'prev' => "上一页", 
         'next' => "下一页", 
         'first'=> "首页", 
         'last' => "末页"
      );                 

<?php
require_once "../dbdb/DBDA.class.php";
require_once "../dbdb/page.class.php";

$sql3 = "select  * from cargo WHERE is_delete = '0'";

if (!empty($_GET)) {
    if ($lname = isset($_GET['lname'])){
        $lname = $_GET['lname'];
    }
    if ($name = isset($_GET['name'])){
        $name = $_GET['name'];
    }

    if(isset($_GET['number'])){
        $number = $_GET['number'];
    };

    $sql3 .= !empty($lname) ? " and lname like '%{$lname}%' " : "";
    $sql3 .= !empty($name) ? " and name like '%{$name}%' " : "";
    $sql3 .= !empty($number) ? " and number like '%{$number}%' " : "";

}

$table = "(".$sql3 .") as t ";