/** Add the sql to perform a search.
    *
    * @param Gdn_SQLDriver $Sql
    * @param string $Columns a comma seperated list of columns to search on.
    */
	public function AddMatchSql($Sql, $Columns, $LikeRelavenceColumn = '') {
      if ($this->_SearchMode == 'like') {
         if ($LikeRelavenceColumn)
            $Sql->Select($LikeRelavenceColumn, '', 'Relavence');
         else
            $Sql->Select(1, '', 'Relavence');

         $Sql->BeginWhereGroup();

         $ColumnsArray = explode(',', $Columns);
         foreach ($ColumnsArray as $Column) {
            $Column = trim($Column);

            $Param = $this->Parameter();
            $Sql->OrWhere("$Column like $Param", NULL, FALSE, FALSE);
         }

         $Sql->EndWhereGroup();
      } else {
         $Boolean = $this->_SearchMode == 'boolean' ? ' in boolean mode' : '';

         $Param = $this->Parameter();
         $Sql->Select($Columns, "match(%s) against($Param{$Boolean})", 'Relavence');
         $Param = $this->Parameter();
         $Sql->Where("match($Columns) against ($Param{$Boolean})", NULL, FALSE, FALSE);
      }
	}