title: Ensure username and email address are unique
body: <p>I am trying to verify whether or not a username and email address exist in my database and have tried to do a if, elseif, else statement to no avail.</p>
  
  <p>I want to first run a check to see if the username is fine - obviously if not, an echo statement will appear. If the username doesn't exist, run an elseif statement to see if the email address is unique - again if not, another echo statement will appear. For the final statement, if all other conditions return false, I want to run the below code so that the user's input is submitted to the database.</p>
  
  <p>I initially tried to declare two variables with a statement to check if the username=$username and email_address=$email_address then check to see if the number of rows returned from a mysqli_query is more than 1 for the username. I entered an elseif statement with the same but for email address but then I had an else statement with the below code in {} brackets.</p>
  
  <p>I have deleted the original code because too many errors were thrown up, and was probably too convoluted and messy when a more elegant way to do what I was exists.</p>
  
  <p>Any help would be appreciated.</p>
  
  <pre><code>if(isset($_POST['submit']))
      {
  $sql = "INSERT INTO users (first_name, last_name, username, email_address, password,    gender, city, country, verification_code, verified, sign_up_date) VALUES (
  '$first_name',
  '$last_name',
  '$username',
  '$email_address',
  '$password',
  '$gender',
  '$city',
  '$country',
  '$verification_code',
  '1',
  '$sign_up_date')";
      $result = mysqli_query($conn,$sql);
      header("Location:confirmation.php");
  }   
  </code></pre>