public function getAlL(){
try{

      $sql = "   SELECT tbl_abstract.abstract_id, tbl_abstract.first_name, tbl_abstract.last_name,tbl_abstract.content, tbl_author.afirst_name, tbl_author.alast_name, tbl_author.aaffilition FROM tbl_abstract  INNER JOIN tbl_author ON  tbl_abstract.abstract_id = tbl_author.abstract_id GROUP BY  tbl_abstract.abstract_id  " ;

      $stmt= $this->pdo->prepare($sql);
      $stmt->execute();
      $count =  $stmt ->rowCount();
      while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
      ?>

         <table class="table" >
          <tr>
            <td  align="center" >
               //data from tbl_abstract
               <?php echo $row["abstract_id"];  ?>. <?php print($row["abstract_title"]); ?>
                <?php echo $row["first_name"].'&nbsp;'.$row["last_name"]; ?>,

                //data from tbl_author
                <?php echo $row["afirst_name"].'&nbsp;'.$row["alast_name"];?>
            </td>
          </tr>
          <tr>
            <td align="center" ">
               //data from tbl_abstract
               <?php print($row["content"]); ?>
            </td>
          </tr>

        </table>
      <?php
     }
}catch(PDOException $e){
   echo $e->getMessage();
   return false;
}