php多条件模糊查询怎么实现

                //<!--php模糊查询 -->
        //接收post传值
$name = I(&#39;post.name&#39;);  
$mail = I(&#39;post.mail&#39;);  
$age = I(&#39;post.age&#39;);  
if(!empty($name)){  
                //封装模糊查询 赋值到数组 
$where[&#39;name&#39;] = array(&#39;like&#39;,&#39;%&#39;.$name.&#39;%&#39;); 
}  
if(!empty($mail)){  
$where[&#39;mail&#39;] = array(&#39;like&#39;,&#39;%&#39;.$mail.&#39;%&#39;);  
}  
if(!empty($age)){  
$where[&#39;age&#39;] = $age;  
} 
                //如果查询条件是OR的关系请打开，一般都是AND关系。 
$where[&#39;_logic&#39;]=&#39;OR&#39;;  
$test = M(&#39;table&#39;)->where($where)->select();