in Wordpress, how do i find and display the very first comment from the current publish I'm reading through?

I believe an answer is going to be with SQL.

Any clues? Thanks!

This can be a function that will get 5 recent comments of posts. I must edit this and show the most recent from the publish I'm reading through

function showLatestComments() {
  global $wpdb;  
  $sql = "
   SELECT DISTINCT comment_post_ID, comment_author, comment_date_gmt, comment_approved, SUBSTRING(comment_content,1,100) AS com_excerpt 
   FROM $wpdb->comments 
   WHERE comment_approved = '1'
   ORDER BY comment_date_gmt DESC 
   LIMIT 5";  
 $comments = $wpdb->get_results($sql);  
 $output .= '<h2>latest comments</h2><ul id="comm">';  
 foreach ($comments as $comment) { 
   $output .= '<li><strong>'. $comment->comment_author . ' said</strong> : "' . strip_tags($comment->com_excerpt). '..."</li>';
 $output .= '</ul>';  
 echo $output;  
}//end function