Displaying info or rather not displaying

[harkly]

I have a list of items that don't show if they have not been selected. Now I don't want to show the topic if none of the items are selected. This is what shows::

Music I listen to:

My question is what is the best way to go about not displaying "Music I listen to:"?

Right now I can get the results I want when I use this in my code below

  if ($band == null)

I am pretty sure I need to set it up so that it runs thru all of the different types of music but not sure what would be the best way to do that.

  if ($band == null && barbershpr == null && classical == null && etc)

My code so far--

 
$sql = mysql_query("SELECT * FROM music WHERE userId = 'test'");
$results = mysql_fetch_array( $sql );


 if ($band == null)
    { 
      echo " Blank \n";  

    }

  else
    {
      echo "  <br><br>Music I listen to:
              <span class='text'>
      \n";

  $sql = mysql_query("SELECT * FROM music WHERE userId = 'kelly'");

  while($r = mysql_fetch_array($sql)) {

    $string = "";

      if ($r['band']) $string .= "Band, ";
      if ($r['barbershop']) $string .= "Barbershop, ";
      if ($r['classical']) $string .= "Classical, ";
      if ($r['country']) $string .= "Country, ";
      if ($r['dance']) $string .= "Dance, ";
      if ($r['electric']) $string .= "Electroinical, ";
      if ($r['folk']) $string .= "Folk, ";
      if ($r['jazz']) $string .= "Jazz, ";
      if ($r['metal']) $string .= "Metal, ";
      if ($r['opera']) $string .= "Opera/Musicals, ";
      if ($r['orchestra']) $string .= "Orchestra, ";
      if ($r['punk']) $string .= "Punk Rock, ";
      if ($r['ragtime']) $string .= "Ragtime, ";
      if ($r['rap']) $string .= "Rap/Hip Hop, ";
      if ($r['reggae']) $string .= "Reggae/Ska, ";
      if ($r['religious']) $string .= "Religious, ";
      if ($r['rock_pop']) $string .= "Rock/Pop/Alternative, ";
      if ($r['world']) $string .= "World, ";
      if ($r['othr_music']) $string .= $r['othr_music_txt'];

      $string = rtrim($string, ", ");

      echo " $string \n";
    }
}

Right now I am having it echo "Blank" for testing purposes.

[bradgrafelman]

For one, that looks like a very bad/unnormalized DB design. You have a separate column for each type/genre of music? What happens if you forget a genre/type... you have to modify the DB structure?

Instead, you should have a single "genre" reference table that has two columns - id (AUTO_INCREMENT), genre. Then, you'd create a "user_genre" table that matches users to genres they select; this table could again be composed only two fields - user_id, genre_id.

At any rate, for displaying the genres, don't output anything until after you've collected the data. That way, if no data was returned, then you simply don't output anything (or you could output something like "None").

EDIT: Forgot to mention... you might want to stop and read a few good articles on Database Normalization before you get much farther along with writing the code. Planning and creating a normalized DB schema is one of the things you should do (IMHO) before you write even a single line of code.