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After clicking login on the login page, the data cannot be queried and the login cannot be successful, but the query operation in the database can be successful. What is the reason?

<?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' ";

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

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

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

switch($user){

    case 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'];

                   $_SESSION['admin_id']=$row['admin_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 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!=""){

                   $url="index_teacher.php";

                   $_SESSION['teacher_name']=$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>";

                }

                break;

    default :break;

}  

mysqli_close($conn);

?>

移动用户-2386203移动用户-23862031445 days ago1528

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  • 灭绝师太

    灭绝师太2021-03-08 09:22:52

    Whether the data can be obtained by back-end breakpoint printing

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