多条件查询

<h1>汽车信息</h1>
<?php
require("../0428/DBDA.class.php");   引用文件
$db = new DBDA();

//1.如果没有提交数据，显示所有
//2.如果有提交数据，根据关键字查询显示
$name="";
$tj1 = " 1=1 "; //第一个条件，对应名称
$tj2 = " 1=1 "; //第二个条件，对应系列
if(!empty($_POST["name"]))
{
$name = $_POST["name"];
$tj1 = " name like '%{$name}%' ";
}
if(!empty($_POST["brand"]))
{
$brand = $_POST["brand"];
$tj2 = " brand = '{$brand}' ";
}
//总条件
$tj = " {$tj1} and {$tj2}";

$sql = "select * from car where ".$tj;
echo $sql;
?>

<form action="chaxun.php" method="post">
<div>名称：<input type="text" name="name" value="<?php echo $name ?>" /> 系列：<input type="text" name="brand" /> <input type="submit" value="查询" /></div>
</form>
<br />
<table width="100%" border="1" cellpadding="0" cellspacing="0">
<tr>
<td>代号</td>
<td>名称</td>
<td>系列</td>
<td>上市时间</td>
<td>价格</td>
</tr>
<?php

/*$sql = "select * from car";
$name="";
if(!empty($_POST["name"]))
{
$name = $_POST["name"];
$sql = "select * from car where name like '%{$name}%' ";
}*/

$arr = $db->query($sql);

foreach($arr as $v)
{
$str = str_replace($name,"<span style='color:red'>{$name}</span>",$v[1]);
echo "<tr>
<td>{$v[0]}</td>
<td>{$str}</td>
<td>{$v[2]}</td>
<td>{$v[3]}</td>
<td>{$v[7]}</td>
</tr>";
}

?>
</table>

</body>
</html>