怎么修改数据库中内容

<!--?php<br /-->
//######################修改课题界面3##########################<br>
  include "config.php";<br>
  include "admin_header.php";<br>
?> <br>
<title>修改课题</title><br>
<!--?php<br /-->
   $query="update $jiaoshi_table set subject='$subject1' where id='$id'";<br>
   mysql_query("set names 'GB2312'");<br>
   $result=mysql_query($query);<br>
   $query="update $jiaoshi_table set teacher='$teacher1' where id='$id'";<br>
   mysql_query("set names 'GB2312'");<br>
   $result=mysql_query($query);<br>
   $query=mysql_query("update $jiaoshi_table set zhicheng='$zhicheng1' where id='$id'");<br>
   mysql_query("set names 'GB2312'");<br>
   $result=mysql_query($query);<br>
   $query=mysql_query("update $jiaoshi_table set specialized='$specialized1' where id='$id'");<br>
   mysql_query("set names 'GB2312'");<br>
   $result=mysql_query($query);<br>
   $query=mysql_query("update $jiaoshi_table set code='$select' where id='$id'");<br>
   mysql_query("set names 'GB2312'");<br>
   $result=mysql_query($query); <br>
   $query="update $jiaoshi_table set beizhu='$introduction' where id='$id'";<br>
   mysql_query("set names 'GB2312'");<br>
   $result=mysql_query($query);<br>
   <br>
   $query="select number as sn,surplus as ssn from $jiaoshi_table where id='$id'";<br>
mysql_query("set names 'GB2312'");<br>
$result=mysql_query($query);<br>
$row=mysql_fetch_array($result);<br>
if($number1<$row[sn])<br>
{<br>
if($number1<($row[sn]-$row[ssn]))<br>
{<br>
echo"<p align="\"center\""><font color="\"#FF0000\""><b><big>人数不能少于现已选题人数，人数列修改失败！</big></b></font>";<br>
echo"<meta http-equiv="\"refresh\"" content="\"2;url=alter_keti.php\"">";<br>
exit;<br>
}<br>
else<br>
{<br>
    
$query2=mysql_query("update $jiaoshi_table set number='$number1' where id='$id'");<br>
$query3=mysql_query("update $jiaoshi_table set surplus=surplus-($row[sn]-$number1) where id='$id'");<br>
mysql_query("set names 'GB2312'");<br>
   
$result1=mysql_query($query3);<br>
<br>
}<br>
}<br>
else<br>
{<br>
$query4=mysql_query("update $jiaoshi_table set number='$number1' where id='$id'");<br>
$query5=mysql_query("update $jiaoshi_table set surplus=surplus+($number1-$row[sn]) where id='$id'");<br>
mysql_query("set names 'GB2312'");<br>
   
$result2=mysql_query($query5);<br>
<br>
   
}<br>
<br>
if($result==true)<br>
{<br>
   echo"</p><p align="\"center\""><font color="\"#FF0000\""><b><big>修改课题成功！</big></b></font>";<br>
   echo "<meta http-equiv="\"refresh\"" content="\"1;url=alter_keti.php\"">";<br>
   exit;<br>
 }<br>
 else<br>
 {<br>
   echo"</p><p align="\"center\""><font color="\"#FF0000\""><b><big>修改出错，请返回重新修改</big></b></font></p>";<br>
   echo "<meta http-equiv="\"refresh\"" content="\"1;url=alter_keti.php\"">"; <br>
   exit;