php 查询

<h1>租房信息</h1>
<?php
$db = new MySQLi("localhost","root","456","asdadads");
$tj = "1=1";
$tj1 = "1=1";
$name = "";
if(!empty ($_POST["name"]))
{
    $name = $_POST["name"];
    $tj = "keyword like '%{$name}%'";
}
if(!empty ($_POST["area"]))
{
    $area = $_POST["area"];
    $tj1= "$area = '{$area}'";
    }
?>
<form action="zufang.php" method="post">
<div>
关键字：
<input type="text" name="name" value="<?php echo $name ?>" /> 
请输入区域：
<input type="text" name="area" />
<input type="submit" value="查询" /> 


</div>
</form>
</br>
<table width="100%" border="1" cellpadding="0" cellspacing="0">
<tr>
    <td>唯一标识</td>
    <td>关键字</td>
    <td>所属区域</td>
    <td>使用面积（平米）</td>
    <td>租金（每月）</td>
    <td>租房类型</td>
    <td>房屋类型</td>
</tr>
<?php
//$db = new MySQLi("localhost","root","456","asdadads");
$sql = "select * from zufang where {$tj} and {$tj1}";
echo $sql;
$r= $db->query($sql);
$attr= $r->fetch_all();
if(count($attr)>0)
{
foreach( $attr as  $v)
{
    $str = str_replace($name,"<mark>{$name}</mark>",$v[1]);
    echo "
    <tr>
    <td>{$v[0]}</td>
    <td>{$str}</td>
    <td>{$v[2]}</td>
    <td>{$v[3]}</td>
    <td>{$v[4]}</td>
    <td>{$v[5]}</td>
    <td>{$v[6]}</td>
    </tr>";
    
    }
}
el
    {
        echo "<script>alert('没有查到数据');</script>";
    }
    
?>