Display different table from database based on select dropdown

I have 3 different table for each role which is Admin, Mechanic, and User. What I want is to display the table from database for each table (bootstrap table and dataTable) based on selected from dropdown select

Here is my code:

<div class="container hero">
            <div class="row">
                <div class="col offset-0">
                  <select>
                        <optgroup label="Role">
                            <option value selected>Admin</option>
                            <option value>Mechanic</option>
                            <option value>User</option>
                        </optgroup>
                    </select>
                  </div>
            </div>
            <div class="row">
            <div class="col" style="height: 71px;">
                <h1 style="font-family: Roboto, sans-serif; font-weight: 300;">Admin</h1>
            </div>
                <div class="col-md-8 offset-md-2">
                  <div class="bootstrap_datatables">
                    <div class="container py-1">
                      <div class="row py-1">
                        <div class="col-lg-10 mx-auto">
                          <div class="card rounded shadow border-0">
                            <div class="card-body p-3 bg-white rounded">
                              <div class="table-responsive">
                                <table id="myTable" style="width:100%" class="table table-striped table-bordered">
                                  <thead>
                                    <tr>
                                      <th>#</th>
                                      <th>ID</th>
                                      <th>Name</th>
                                      <th>Role</th>
                                      <th>View</th>
                                    </tr>
                                  </thead>
                                  <tbody>
                                  <?php
                                    // $sql = "SELECT * FROM admin";
                                    // $result = mysqli_query($connect, $sql);
                                    
                                    //     if(mysqli_num_rows($result) > 0){
                                    
                                    //     $i = 1;
                                    
                                    //     while ($row = mysqli_fetch_assoc($result)) {
                                    //         $Name = $row['PERSON_NAME'];
                                    

                                    //             echo "<tr style='font-size:18px;'>";
                                    //             echo "<td class='align-middle'>" . $i; $i++ . "</td>";
                                    //             echo "<td class='align-middle'>" . $Name . "</td>";
                                    //             echo "<td class='align-middle'></td>";
                                    //             echo "<td class='align-middle'></td>";
                                    //             echo "<td class='align-middle'></td>";
                                    //             echo "</tr>";
                                    //         }
                                    //     } else {
                                    //         echo "<tr>";
                                    //         echo "<td colspan='7' class='table-active align-middle'>No Record in Database</td>";
                                    //         echo "</tr>";
                                    //     }
                                    ?>
                                  </tbody>
                                </table>
                              </div>
                            </div>
                          </div>
                        </div>
                      </div>
                    </div>
                  </div>
              </div>
            </div>
        </div>

$sql = "SELECT * FROM admin;

$sql = "SELECT * FROM mechanic;

$sql = "SELECT * FROM user;

This is the example of SQL statement where I display data from table admin, mechanic, and user.

So, how can I display table from table Admin in database if admin is selected in dropdown same goes to mechanic and user

Extra request: Boost style of the dropdown select for me if you wish make it look slicker.