<?php

session_start();

error_reporting(E_ERROR); 

$zh=$_POST['zh'];

$password=$_POST['password'];

$user=$_POST['user'];

if(!isset($user)) {

    echo "<script> Alert('请选择用户类型');</script>";

    echo "<script> History.go(-1);</script>";

}

$conn=mysqli_connect("localhost","8admin","8admin")or die('连接数据库失败');

$db=mysqli_select_db($conn,"8_com");

$sql1 ="SELECT*FROM admin WHERE admin_id ='$zh' AND password='$password' ";

$sql2="select * from teacher where teaching_id ='$zh' and password='$password' ";

$sql3="select * from student where stuno ='$zh' and password='$password' ";

mysqli_query($conn,"set name utf8");

switch($user){

    Fall 1 :$result=mysqli_query($conn,$sql)or die('查询不到'); 

               $row = mysqli_fetch_array($conn,$result);

             $count=$row[0];

             if($count!=""){

                  $url="index_admin.php";

$_SESSION['admin_name']=$row['name'];

                   "."location.href='".$url."'"."</script>";

               }

             else {

                  echo "<script> warning('账户或密码错误'); </script>";

                    echo "<script> History.go(-1);</script>";

                }

              break;

   Fall 2:$result=mysqli_query($sql2, $conn);  

        $result=mysqli_query($sql2,$conn)or die('查询不到'); 

               $row = mysqli_fetch_array($result);

               $count=$row[0];

               if($count!=""){

                                                        $_SESSION['teacher_name']=$row['name'];

                   $_SESSION['teacher_id']= $row['teach_id'];

                   echo "<script type='text/javascript'>"."location.href='".$url."'"."</script>";

               }

             else {

                echo "<script> Alert('账户或密码错误');</script>";

                    echo "<script> History.go(-1);</ script>";

                }

                break;

    case 3:$result=mysqli_query($sql3,$conn);  

        $result=mysqli_query($sql3,$conn)or die('查询不到'); 

               $row = mysqli_fetch_array($result);

               $count=$row[0];

             if($count!=""){

                  $url="index_stu.php";

                   $_SESSION[ 'stu_name']=$row['name'];

                   $_SESSION['stu_id']=$row['stuno'];

                   echo "<script type='text/javascript'>"." location.href='".$url."'"."</script>";

               }

             else {

                  echo "<script> Alert('账户或密码错误');</ script>";

                    echo "<script> History.go(-1);</script>";

                }

                default : Pause;

}  

mysqli_close($conn);

?>