title: What is meaning of 0 in mysql_result($res, 0, "id");?
body: <p>I searched on google but didn't find anything that could help me!</p>
  
  <pre><code>$sql = "SELECT id FROM users WHERE username = '". mysql_real_escape_string($u) ."' ";
  $res = mysql_query($sql);
  if (mysql_num_rows($res) == 1) 
  {
  $id = mysql_result($res, 0, "id");        // got id of username
  } 
  </code></pre>
  
  <p>What does 0 represents? </p>