สอบถามปัญหา checkbox หน่อยครับว่ามันทำงานอย่างไร จะเอาไป select DB

<form id="form2" name="form1" method="post" action="">
  Dial
  <input type="checkbox" name="dial" id="checkbox" />
</form>

<br>

<table width="100%" border="1">
  <tr>
    <td><center> àºÍÃìµé¹·Ò§ <center/></td>
    <td><center> àºÍÃì»ÅÒ·ҧ <center/></td>
    <td><center> ÃÐÂÐàÇÅÒ㹡ÒÃÊ·¹Ò <center/></td>
    <td><center> ÇѹáÅÐàÇÅÒ㹡ÒÃÊ·¹Ò <center/></td>
  </tr>
<?php
		
		$sql="select * from cdr where (src='$numberphone' or dst='$numberphone') and lastapp=$'dial' ";
		$query=mysql_query($sql);
		while($rs=mysql_fetch_array($query))
		{
			$src = $rs[2];
			$dst = $rs[3];
			$calldate = $rs[0];
			$billsec = $rs[10];