I have a mysql DB which directly stores links to different sites.
I fetch the link from DB and store it in a variable like this:
$tdl = $row["file"];
<a href="<?php echo $tdl ;?>" target="_blank"><b><u>VIEW PDF DOCUMENT</b></u></a>
Try This,
<a href="<?php echo "http://".$tdl ;?>" target="_blank"><b><u>VIEW PDF DOCUMENT</u></b></a>