如何实现多个查找框内只需填写至少一个查找内容即可进行查找
apply.html
<html>
<head>
   <title>A new Application for a classroom</title>
</head>
<body>
   <h1>CRMS - New classroom Entry</h1>
   <form action="2.php" method="post">
     <table border="0">
       <tr>
         <td>Classroom ID</td>
          <td><input type="text" name="Cno" maxlength="13" size="13"></td>
       </tr>
       <tr>
         <td>Course ID</td>
         <td> <input type="text" name="CID" maxlength="30" size="30"></td>
       </tr>
       <tr>
         <td colspan="2"><input type="submit" value="Register"></td>
       </tr>
     </table>
   </form>
</body>
</html>
2.php
<html>
<head>
   <title>A new Application for a classroom</title>
</head>
<body>
<h1>CRMS - New classroom Entry Results</h1>
<?php
   // create short variable names
   $Cno=$_POST['Cno'];
   $CID=$_POST['CID'];
   if (!$Cno) {$Cno = "%";}
   if (!$CID) {$CID = "%";}
   if (!get_magic_quotes_gpc()) {
     $Cno = addslashes($Cno);
     $CID = addslashes($CID);
   }
$con = mysql_connect("localhost","root","");
//通过服务器locahost建立连接,用户名为root,无密码
if (!$con)
   {
   die('Could not connect: ' . mysql_error());
   }
mysql_select_db("crms", $con);
$search_classroom = "SELECT * FROM use2  
                      WHERE Cno  LIKE '{$Cno}' AND  CID LIKE $CID";
$result = mysql_query($search_classroom, $con);
while($row = mysql_fetch_array($result))
   {
   echo $row['Cno'];
   echo $row['CID'];
   echo "<br />";
   }
mysql_close($con)
?>
</body>
</html>
为什么这样不能实现当Classroom ID 或者Course ID没有填写时,任然能够成功搜索。我已经写了  if (!$Cno) {$Cno = "%";}
   if (!$CID) {$CID = "%";}如果没有填就用通配符,而且查询时也用了LIKE(如果查询时LIKE全部换为=则成功)。为什么?在线等!
------解决方案--------------------
因为你用like了。去查下mysql手册。