Maria DB服务器错误

Question

您的SQL语法有错误；查看与您的MariaDB服务器版本相对应的手册，以获取在Near附近使用的正确语法

<?php
    include 'includes/conn.php';

    if (isset($_POST['reg'])) {
        # code...

        $username = mysqli_real_escape_string($conn,$_POST['username']);
        $role = mysqli_real_escape_string($conn,$_POST['role']);
        $email = mysqli_real_escape_string($conn,$_POST['email']);
        $pass = mysqli_real_escape_string($conn,$_POST['password']);

        if (strlen($pass)<8) {
            # code...

            echo "
                 <script>
                    alert('Password Should Be Minimum 8 Characters!')
                 </script>
            ";
            exit();
        }

        $check_email = "SELECT * FROM users WHERE email='$email'";
        $run_email = mysqli_query($conn,$check_email);

        $check = mysqli_num_rows($run_email);

        if ($check==1) {
            # code...

            echo "
                 <script>
                    alert('Email Is Already Exist Try Another')
                 </script>
            ";
        }

        $insert = "INSERT INTO users('username', 'role', 'email', 'pass') VALUES ($username,$role,$email,$pass)";

        if ($conn->query($insert) === TRUE) {
            echo "<script>alert(Your Account Has Been Created Successfully!)</script>";
        } else {
            echo "<script>alert(Oops! Registration Failed,Please Try Again)</script>" . $insert . "<br>" . $conn->error;
        }
    }
 ?>