[Plugin: Woocommerce booking plugin]

Im using a plugin called woocommerce booking plugin by tychesoftwares.

I have added a custom checkout field where the customer can insert the name of the attendee of a course. This field is save to the wp_metapost with my own defined meta_key.

On the admin page of this plugin there is a page called “View bookings”.
I would like to display my custom field on this page.
I know what function i need to edit but I cannot get my custom mysql query to work. Can someone please show me how to do the mysql query correct?

Part of the function:

function woocommerce_history_page() {

				if (isset($_GET['action']))
				{
					$action = $_GET['action'];
				}
				else
				{
					$action = '';
				}
				if ($action == 'history' || $action == '')
				{
					$active_settings = "nav-tab-active";
				}

				?>

				<p></p>

				<!-- <h2 class="nav-tab-wrapper woo-nav-tab-wrapper">
				<a href="admin.php?page=woocommerce_history_page&action=history" class="nav-tab <?php echo $active_settings; ?>"> <?php _e( 'Booking History', 'woocommerce-ac' );?> </a>
				</h2> -->

				<?php

				if ( $action == 'history' || $action == '' )
				{
					global $wpdb;

					$query_order = "SELECT DISTINCT order_id FROM <code>&quot; . $wpdb->prefix . &quot;woocommerce_order_items</code>  ";
					$order_results = $wpdb->get_results( $query_order );

					$var = $today_checkin_var = $today_checkout_var = $booking_time = "";

					$booking_time_label = get_option('book.item-meta-time');
				//	echo $booking_time_label;

					foreach ( $order_results as $id_key => $id_value )
					{
						$order = new WC_Order( $id_value->order_id );

						$order_items = $order->get_items();

						$terms = wp_get_object_terms( $id_value->order_id, 'shop_order_status', array('fields' => 'slugs') );
						if( (isset($terms[0]) && $terms[0] != 'cancelled') && (isset($terms[0]) && $terms[0] != 'refunded'))
						{
						$today_query = "SELECT * FROM <code>&quot;.$wpdb->prefix.&quot;booking_history</code> AS a1,<code>&quot;.$wpdb->prefix.&quot;booking_order_history</code> AS a2 WHERE a1.id = a2.booking_id AND a2.order_id = '".$id_value->order_id."'";
						$results_date = $wpdb->get_results ( $today_query );

						$c = 0;
						foreach ($order_items as $items_key => $items_value )
						{
							$start_date = $end_date = $booking_time = "";

							$booking_time = array();
							//print_r($items_value);
							if (isset($items_value[$booking_time_label]))
							{
								$booking_time = explode(",",$items_value[$booking_time_label]);
							}

							$duplicate_of = get_post_meta($items_value['product_id'], '_icl_lang_duplicate_of', true);
							if($duplicate_of == '' && $duplicate_of == null)
							{
								$post_time = get_post($items_value['product_id']);
								if (isset($post_time))
								{
									$id_query = "SELECT ID FROM <code>&quot;.$wpdb->prefix.&quot;posts</code> WHERE post_date = '".$post_time->post_date."' ORDER BY ID LIMIT 1";
									$results_post_id = $wpdb->get_results ( $id_query );
									if( isset($results_post_id) ) {
										$duplicate_of = $results_post_id[0]->ID;
									}
									else
									{
										$duplicate_of = $items_value['product_id'];
									}
								}
								else {
									$duplicate_of = $items_value['product_id'];
								}
							}
						//	echo "<pre>";echo $id_value->order_id; print_r($booking_time);echo "</pre>";
							if ( isset($results_date[$c]->start_date) )
							{
								if (isset($results_date[$c]) && isset($results_date[$c]->start_date)) $start_date = $results_date[$c]->start_date;

								if (isset($results_date[$c]) && isset($results_date[$c]->end_date)) $end_date = $results_date[$c]->end_date;

								if ($start_date == '0000-00-00' || $start_date == '1970-01-01') $start_date = '';
								if ($end_date == '0000-00-00' || $end_date == '1970-01-01') $end_date = '';
								$amount = $items_value['line_total'] + $items_value['line_tax'];
								if(is_plugin_active('bkap-printable-tickets/printable-tickets.php'))
								{
									$var_details = apply_filters('bkap_view_bookings',$id_value->order_id,$results_date[$c]->booking_id,$items_value['qty']);
								}
								else
								{
									$var_details = array();
								}
								if (count($booking_time) > 0)
								{
								foreach ($booking_time as $time_key => $time_value)
								{
									if(array_key_exists('ticket_id',$var_details) && array_key_exists('security_code',$var_details))
									{

										$var .= "<tr>
										<td>".$id_value->order_id."</td>
										<td>".$order->billing_first_name." ".$order->billing_last_name."</td>
<td>".$results."</td>

										<td>".$items_value['name']."</td>
										<td>".$start_date."</td>
										<td>".$end_date."</td>
										<td>".$time_value."</td>
										<td>".$amount."</td>
										<td>".$order->completed_date."</td>
										".$var_details['ticket_id']."
										".$var_details['security_code']."
										<td><a href=\"post.php?post=". $id_value->order_id."&action=edit\">View Order</a></td>
										</tr>";
									}
									else
									{
										$var .= "<tr>
										<td>".$id_value->order_id."</td>
										<td>".$order->billing_first_name." ".$order->billing_last_name."</td>
<td>".$results."</td>
										<td>".$items_value['name']."</td>
										<td>".$start_date."</td>
										<td>".$end_date."</td>
										<td>".$time_value."</td>
										<td>".$amount."</td>
										<td>".$order->completed_date."</td>
										<td><a href=\"post.php?post=". $id_value->order_id."&action=edit\">View Order</a></td>
										</tr>";
									}
									//foreach ($results_date as $key_date => $value_date )
									{
										/*$start_date_r = $end_date_r = '';
										if (isset($value_date->start_date)) $start_date_r = $value_date->start_date;
										if (isset($value_date->end_date)) $end_date_r = $value_date->end_date;

										if ($start_date_r == '0000-00-00' || $start_date_r == '1970-01-01') $start_date_r = '';
										if ($end_date_r == '0000-00-00' || $end_date_r == '1970-01-01') $end_date_r = '';*/

										if ( $start_date == date('Y-m-d' , current_time('timestamp') ) )
										{
										if(array_key_exists('ticket_id',$var_details) && array_key_exists('security_code',$var_details))

											{
												$today_checkin_var .= "<tr>
												<td>".$id_value->order_id."</td>
												<td>".$order->billing_first_name." ".$order->billing_last_name."</td>
<td>".$results."</td>
												<td>".$items_value['name']."</td>
												<td>".$start_date."</td>
												<td>".$end_date."</td>
												<td>".$time_value."</td>
												<td>".$amount."</td>
												<td>".$order->completed_date."</td>
												".$var_details['ticket_id']."
												".$var_details['security_code']."
												<td><a href=\"post.php?post=". $id_value->order_id."&action=edit\">View Order</a></td>
												</tr>";
											}