如何php下拉菜单读取数据库

<?php  $link=mysql_connect("127.0.0.1","root","12345678");    if(!$link) echo "没有连接成功!";   mysql_select_db("busap", $link);          //选择数据库 ?><tr>     <td width="9%" height="26" nowrap="nowrap"><div align="center"><font size="5">选择线路</font></div></td>     <td width="22%" nowrap="nowrap"><label>       <select name="select">   <?php  //控制查询条件$q = "SELECT * FROM line ORDER BY linename asc";   mysql_query("SET NAMES GB2312"); //防止乱码$rs = mysql_query($q); //获取数据集$assoc= mysql_num_rows($rs);///影响的行数 , 原来用了mysql_fetch_assoc$row=mysql_fetch_array($rs); //只需要补充回这一行. $xl=$row[linename]?>          <option selected="selected">选择线路</option>    <?php do { ?>         <option><?php echo $row[linename]; ?></option>    <?php }while($row=mysql_fetch_array($rs)); ?>       </select>     </label></td>   </tr>   <tr>     <td height="26" nowrap="nowrap"><div align="center"><font size="5">车辆自编号</font></div></td>     <td nowrap="nowrap"><label> <select name="select4">   <?php //控制查询条件$q = "SELECT * FROM `busname` where linename='{$_REQUEST['select']}' ORDER BY busname asc";   mysql_query("SET NAMES GB2312"); //防止乱码$rs = mysql_query($q); //获取数据集$assoc= mysql_num_rows($rs);///影响的行数 , 原来用了mysql_fetch_assoc$row1=mysql_fetch_array($rs); //只需要补充回这一行. ?>          <option selected="selected">选择车辆</option>    <?php do { ?>         <option><?php echo $row1[2]; ?></option>    <?php }while($row=mysql_fetch_array($rs)); ?>       </select>     </label></td>   </tr>