Adds the discount code ID and Name to the Members List page of Paid Memberships Pro

pmpro_discount_on_members_list.php

<?php
//To add Discount Code Information to Members List
//Add Discount Code Information Column to Members List Header
function my_pmpro_memberslist_extra_cols_header($theusers)
{
	?>
	<th><?php _e('Discount ID', 'pmpro');?></th>
	<th><?php _e('Discount Code', 'pmpro');?></th>
<?php
}
add_action('pmpro_memberslist_extra_cols_header', 'my_pmpro_memberslist_extra_cols_header');

//Add Discount Code Information to Members List Rows
function my_pmpro_memberslist_extra_cols_body($theuser){
	if(!empty($theuser->data->ID)){
		//grab discount code info
		global $wpdb;
		$disSql = $wpdb->prepare("
			SELECT
			c.id,
			c.code
			FROM {$wpdb->pmpro_discount_codes_uses} cu
			LEFT JOIN $wpdb->pmpro_discount_codes c ON cu.code_id = c.id
			WHERE cu.user_id = %d
			ORDER BY c.id DESC
			LIMIT 1",
			$theuser->ID
		);

		$discount_code = $wpdb->get_row($disSql);
		if (empty($discount_code)){
			echo "<td>None</td><td>None</td>";
		}
		else{
			echo "<td>".$discount_code->id."</td><td>".$discount_code->code."</td>";
		}
	}
}
add_action('pmpro_memberslist_extra_cols_body', 'my_pmpro_memberslist_extra_cols_body');