php - 检查用户名和电子邮件已经存在于php mysql中

Question

检查PHP MySQL中已经存在的用户名和电子邮件，我检查每个输入是否为空，如果没有空，则检查用户名和密码是否已在数据库中，如果不是在数据库中，则ECHO好，代码运行良好，但问题是，当新的条目被输入时，它不会打印好。
代码如下：

<?php
error_reporting(E_ALL & ~E_NOTICE);
require_once('dbcon.php');
if(isset($_POST["create"]))
{
    if (isset($_POST['username']) && !empty($_POST['username'])) {
        $username=mysqli_real_escape_string($conn,trim($_POST['username']));
    }else{
        $empty_username="Username Cannot be empty.";
        echo $empty_username.'<br>';
    }
    if (isset($_POST['email']) && !empty($_POST['email'])) {
        $email=mysqli_real_escape_string($conn,trim($_POST['email']));
    }else{
        $empty_email="Email cannot be empty.";
        echo $empty_email.'<br>';
    }

    if (isset($_POST['category']) && !empty($_POST['category'])) {
        $category=mysqli_real_escape_string($conn,trim($_POST['category']));
    }else{
        $empty_category="Category cannot be empty.";
        echo $empty_category.'<br>';
    }

    if (isset($_POST['password']) && !empty($_POST['password'])) {
        $psw=mysqli_real_escape_string($conn,trim($_POST['password']));
    }else{
        $empty_password="Password cannot be empty";
        echo $empty_password.'<br>';
    }

    if (isset($_POST['re_password']) && !empty($_POST['re_password'])) {
        $repsw=mysqli_real_escape_string($conn,trim($_POST['re_password']));
    }else{
        $empty_repassword="Retype password cannot be empty";
        echo $empty_repassword.'<br>';
    }

    $password=password_hash('$psw',PASSWORD_BCRYPT);
    $date=mysqli_real_escape_string($conn, trim('now()'));
    if($psw!=$repsw)
    {
        echo"password not Matched";
    }
        $sql="select * from account_info where (username='$username' or email='$email');";
        $res=mysqli_query($conn,$sql);
        if (mysqli_num_rows($res) > 0) {
        // output data of each row
        $row = mysqli_fetch_assoc($res);
        if ($username==$row['username'])
        {
            echo "Username already exists";
        }
        elseif($email==$row['email'])
        {
            echo "Email already exists";
        }
        else{
            echo "alright";
        }
    }
}
?>

Answer 1

你只需要在正确的地方添加else条件
试试这个：-

<?php
    error_reporting(E_ALL & ~E_NOTICE);
    require_once('dbcon.php');
    if(isset($_POST["create"]))
    {
        $error = 0;
        if (isset($_POST['username']) && !empty($_POST['username'])) {
            $username=mysqli_real_escape_string($conn,trim($_POST['username']));
        }else{
            $error = 1;
            $empty_username="Username Cannot be empty.";
            echo $empty_username.'<br>';
        }
        if (isset($_POST['email']) && !empty($_POST['email'])) {
            $email=mysqli_real_escape_string($conn,trim($_POST['email']));
        }else{
            $error =1;
            $empty_email="Email cannot be empty.";
            echo $empty_email.'<br>';
        }

        if (isset($_POST['category']) && !empty($_POST['category'])) {
            $category=mysqli_real_escape_string($conn,trim($_POST['category']));
        }else{
            $error = 1;
            $empty_category="Category cannot be empty.";
            echo $empty_category.'<br>';
        }

        if (isset($_POST['password']) && !empty($_POST['password'])) {
            $psw=mysqli_real_escape_string($conn,trim($_POST['password']));
        }else{
            $error = 1;
            $empty_password="Password cannot be empty";
            echo $empty_password.'<br>';
        }

        if (isset($_POST['re_password']) && !empty($_POST['re_password'])) {
            $repsw=mysqli_real_escape_string($conn,trim($_POST['re_password']));
        }else{
            $error = 1;
            $empty_repassword="Retype password cannot be empty";
            echo $empty_repassword.'<br>';
        }

        $password=password_hash('$psw',PASSWORD_BCRYPT);
        $date=mysqli_real_escape_string($conn, trim('now()'));
        if($psw!=$repsw)
        {
            echo "password not Matched";
        }

        if(!$error) {
            $sql="select * from account_info where (username='$username' or email='$email');";
            $res=mysqli_query($conn,$sql);
            if (mysqli_num_rows($res) > 0) {
            // output data of each row
            $row = mysqli_fetch_assoc($res);
            if ($username==$row['username'])
            {
                echo "Username already exists";
            }
            elseif($email==$row['email'])
            {
                echo "Email already exists";
            }
        }else { //here you need to add else condition
            echo "alright";
        }
        }
    }
    ?>