php 搜索练习

<?php
    require_once("connect.php");
    if(isset($_GET['submit'])){
        $name=$_GET['name'];
        $age=$_GET['age'];

        $wherelist=[];
        if(!empty($_GET['name'])){
            $wherelist[]=' name like "%'.$_GET['name'].'%" ';
        }
        if(!empty($_GET['age'])){
            $wherelist[]=' age like '.$_GET['age'];
        }
        if(count($wherelist)>0){
            $where=' where'.implode(" and ", $wherelist);
            mysql_query("set names utf8");
            $ser_query='select * from demotb'.$where;
            $resul=mysql_query($ser_query);
            while ($rows=mysql_fetch_assoc($resul)) {
                # code...
                echo "<table>";
                echo "<tr><td>".$rows['name'].'</td><td>'.$rows['age'].'</td></tr>';
                echo "</table>";
            }
        }
    }
?>

<form action="search.php" method="get">
    <label for="name">Name:</label><input type="text" name="name">
    <label for="age">Age:</label><input type="text" name="age">
    <p><input type="submit" name="submit" value="Search"></p>
</form>