pesquisar o banco de dados com base no valor selecionado do banco de dados

<div class="showsearch"></div>

$(document).ready(function(){
    $('#drop2').on('change',function(){
         var fname = $(this).val();
         // rename your file which include $fname  with get_search_data.php
         if(fname !== ""){
            $.post('get_search_data.php',{fname: fname},function(data){
            $('.showsearch').html(data);
            });
          }
    });
});

• depois desse código, ele deve exibir a $row['fname'] para mostrar o div de pesquisa
• você tem que incluir("connection.php"); em get_search_data.php

<?php
include("connection.php");
if(isset($_POST['fname'])){
$fname = mysqli_real_escape_string($con, $_POST['fname']);
}
$sql1 = 'SELECT * FROM office WHERE fname LIKE "%'.$fname.'%"';
$result = mysqli_query($con, $sql1);

if (mysqli_num_rows($result) > 0) 
    {
        while($row = mysqli_fetch_assoc($result)) {
        echo  $row["fname"]; // this data should appear in showsearch div
    }
} else {
    echo "0 results";
}
mysqli_close($con);
?>