How to make exact keyword search appear first?

I made a mysql/php search engine in which I added google url with keywords google search engine and another yahoo url with keywords yahoo search engine. If I type google search engine on the search box how do I make google url appear first?

This is the code:

//connect to database
  mysql_connect("","","");
  mysql_select_db("");

   //explode out search term
   $search_exploded = explode(" ",$search);

   foreach($search_exploded as $search_each)
   {

        //construct query
    $x++;
    if ($x==1)
     $construct .= "Keywords LIKE '%$search_each%'";
    else
     $construct .= " OR Keywords LIKE '%$search_each%'";

   }

  //echo outconstruct
  $constructx = "SELECT * FROM searchengine WHERE $construct";

  $construct = "SELECT * FROM searchengine WHERE $construct LIMIT $s,$e";
  $run = mysql_query($constructx);

  $foundnum = mysql_num_rows($run);


  $run_two = mysql_query("$construct");

  if ($foundnum==0)
   echo "No results found for <b>$search</b>";
  else

Solution

To find count of entries, you can use SELECT count(*) instead of mysql_num_rows with full query.
To sort results, you need to use "ORDER BY" in query, and some field, which will be criteria of ordering. In your case you can write
$construct = "SELECT * FROM searchengine WHERE $construct ORDER BY Keywords LIMIT $s,$e ";

And don't forget to sanitize your $search.
$search = mysql_real_escape_string($search);