envío de formulario php a la base de datos mysql

*Dulce Y Corto*

Primero verifique que el nombre de usuario o correo electrónico exista o no usando select consulta si el resultado es 0 (significa que no existe), Insert la consulta seguirá adelante

<?php 
   if($_POST['register']){   
      $uname = $_POST['uname'];
      $email = $_POST['email'];
      $name= $_POST['name'];
      $pass= $_POST['pass'];
      $result =  mysqli_query($con, 'SELECT * from TABLE_NAME where email_id = "'.$email.'" or username = "'.$uname.'" ');
       if(mysqli_num_rows($result) > 0){
          echo "Username or email already exists.";
       }else{
         $query = mysqli_query($con , 'INSERT INTO TABLE_NAME (`email_id`, `username`,`name`,`pass`) VALUES("'.$email.'", "'.$email.'", "'.$uname.'","'.$name.'", "'.$pass.'")');

         if($query){
            echo "data are inserted successfully.";
         }else{
          echo "failed to insert data.";
         }
     } 
}
  ?>