使用PHP检查MYSQL是否存在用户和电子邮件

Question

我到处搜索，但是找不到正确的东西。 我有输入：用户名，密码和电子邮件。

我想检查用户名和电子邮件，并知道它们是否存在于数据库中。

如果是，则给出一个na错误；如果没有，则创建一个新帐户。

所以这是我现在的代码：

形式

    <?php 
    function formulary() {
    ?>

    <section class="container">
        <div class="register">
            <h1>Create an account</h1>

            <form method="post">
                <p><input type="text" name="username" value="" placeholder="Username" maxlength="25"></p>
                <p><input type="password" name="password" value="" placeholder="Password" maxlength="25"></p>
                <p><input type="email" name="email" value="" placeholder="E-Mail" maxlength="50"></p>
                <div class="buttons">
                <input type="submit" name="register" value="Register">
                <input type="button" name="cancel" value="Cancel" onClick="window.location='login.php';">
                </div>
            </form>
        </div>
    </section>

    <?php
    }
    ?>

校验

        <?php
        function registNew() {
        $con = mysqli_connect("localhost","root","","work");
        $username = mysqli_real_escape_string($con , $_POST["username"]);
        $password = mysqli_real_escape_string($con , $_POST["password"]);
        $email = mysqli_real_escape_string($con , $_POST["email"]);

        if(mysqli_connect_errno())
        {
            echo "Error MySQL: " .mysqli_connect_errno();
        }

        $sqlUser = "SELECT * FROM users WHERE username = '".$username."'";
        $rs = mysqli_query($con ,$sqlUser);
        $numUsers = mysqli_num_rows($rs);

        if($numUsers > 0) {
            echo "User already exists<br/>";
        }
        else
        {
            $sqlEmail = "SELECT * FROM utilizadores WHERE email = '".$email."'";
            $rs = mysqli_query($con ,$sqlEmail);
            $numEmails = mysqli_num_rows($rs);

            if($numEmails > 0) {
                echo "E-Mail already exists<br/>";
            }
            else 
            {
                $newUser= "INSERT INTO utilizadores(username,password,email) VALUES('$username','$password','$email')";
                if(mysqli_query($con ,$newUser))
                {
                    echo "Account has been created!<br/>";
                    mysqli_close($con);
                    header('Location: login.php');
                }
                else
                {
                    echo "Error at adding user<br/>";
                    header("refresh:5;url=register.php");
                }
            }
        }
    }
    ?>

结束

    <?php
    if(!isset($_SESSION)) {
        session_start();
    }

    if(!isset($_POST["register"]))
    {
        formulary();  
    }
    else
    {
        registNew();
    }
    ?>

创建不存在的帐户的输出为：

添加用户时出错

我在PHP上还很新，所以不知道出什么问题了。 是因为我对用户名和电子邮件使用了相同的变量（check / sql / etc变量）还是我做错了？

知道为什么这行不通吗？

Answer 1

我编辑了registNew函数的第一部分，以检查是否有任何结果。 一切当然都逃脱了，所以你很安全。

function registNew() {
        $con = mysqli_connect("localhost","root","","work");
        $username = mysqli_real_escape_string($con, $_POST["username"]);
        $password = mysqli_real_escape_string($con, $_POST["password"]);
        $email = mysqli_real_escape_string($con, $_POST["email"]);

        if(mysqli_connect_errno())
        {
            echo "Error MySQL: " .mysqli_connect_errno();
        }

        $rsUsers = mysqli_query($con,"SELECT * FROM users WHERE username = '".$username."'");
        $rsEmails = mysqli_query($con,"SELECT * FROM users WHERE email = '".$email."'");
        $numUsers = mysqli_num_rows($rsUsers);
        $numEmails = mysqli_num_rows($rsEmails);

        if($numUsers > 0 || $numEmails > 0) {
            echo "User already exists";
        }
        else
        {

                $newUser= "INSERT INTO users(username,password,email) VALUES('$username','$password','$email')";
                if(mysqli_query($con,$newUser))
                {
                    echo "Account has been created<br/>";
                    /* header('Location: login.php'); */
                }
                else
                {
                    echo "Error at adding user<br/>";
                    header("refresh:5;url=register.php");
                }

        }
    }