怎么修改数据库中内容

//######################修改课题界面3##########################

  include "config.php";

  include "admin_header.php";

?> 




   $query="update $jiaoshi_table set subject='$subject1' where id='$id'";

   mysql_query("set names 'GB2312'");

   $result=mysql_query($query);

   $query="update $jiaoshi_table set teacher='$teacher1' where id='$id'";

   mysql_query("set names 'GB2312'");

   $result=mysql_query($query);

   $query=mysql_query("update $jiaoshi_table set zhicheng='$zhicheng1' where id='$id'");

   mysql_query("set names 'GB2312'");

   $result=mysql_query($query);

   $query=mysql_query("update $jiaoshi_table set specialized='$specialized1' where id='$id'");

   mysql_query("set names 'GB2312'");

   $result=mysql_query($query);

   $query=mysql_query("update $jiaoshi_table set code='$select' where id='$id'");

   mysql_query("set names 'GB2312'");

   $result=mysql_query($query); 

   $query="update $jiaoshi_table set beizhu='$introduction' where id='$id'";

   mysql_query("set names 'GB2312'");

   $result=mysql_query($query);

   

   $query="select number as sn,surplus as ssn from $jiaoshi_table where id='$id'";

		mysql_query("set names 'GB2312'");

		$result=mysql_query($query);

		$row=mysql_fetch_array($result);

		if($number1<$row[sn])

		{

			if($number1<($row[sn]-$row[ssn]))

			{

				echo"
人数不能少于现已选题人数，人数列修改失败！";

				echo"";

				exit;

			}

			else

			{

		    	$query2=mysql_query("update $jiaoshi_table set number='$number1' where id='$id'");

				$query3=mysql_query("update $jiaoshi_table set surplus=surplus-($row[sn]-$number1) where id='$id'");

				mysql_query("set names 'GB2312'");

   				$result1=mysql_query($query3);

				

			}

		}

		else

		{

			$query4=mysql_query("update $jiaoshi_table set number='$number1' where id='$id'");

			$query5=mysql_query("update $jiaoshi_table set surplus=surplus+($number1-$row[sn]) where id='$id'");

			mysql_query("set names 'GB2312'");

   			$result2=mysql_query($query5);

			

   		}

		

		if($result==true)

				{

				   echo"
修改课题成功！";

				   echo "";

				   exit;

				 }

				 else

				 {

				   echo"
修改出错，请返回重新修改
";

				   echo ""; 

				   exit;