SQL返回带有优惠券的Woocommerce订单，但不返回管理员应用的优惠券

Question

我使用的是Woocommerce版本3.8.1。我在WooCommerce中使用优惠券功能。其中一些优惠券是我们的客户在前端应用，而其他一些优惠券是在客户的后端应用。我遇到的问题是，当我报告所使用的优惠券时，我们在后端手动应用的优惠券没有显示出来。我使用了Advanced Order Export For WooCommerce plugin以及一些自定义SQL，但都没有返回所有已实际应用的优惠券。我相信未显示的优惠券是手动应用的。

我的问题是：

1. WooCommerce如何在后端手动存储应用的优惠券（它与在前端输入优惠券的方式不同，
2. 我如何获得一份报告，该报告显示按订单日期应用的优惠券金额总和，
3. 有人使用一些SQL直接查询此数据吗？

我的查询：

select
p.ID as order_id,
p.post_date,
ocl.coupon_id,
ocl.discount_amount,
Max(CASE WHEN pm.meta_key = 'discount_type'      AND  p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS discount_type,
Max(CASE WHEN pm.meta_key = 'coupon_amount'      AND  p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS coupon_amount,          -- Coupon amount 
max( CASE WHEN pm.meta_key = '_billing_email' and p.ID = pm.post_id THEN pm.meta_value END ) as billing_email,
max( CASE WHEN pm.meta_key = '_billing_first_name' and p.ID = pm.post_id THEN pm.meta_value END ) as _billing_first_name,
max( CASE WHEN pm.meta_key = '_billing_last_name' and p.ID = pm.post_id THEN pm.meta_value END ) as _billing_last_name,
max( CASE WHEN pm.meta_key = '_billing_address_1' and p.ID = pm.post_id THEN pm.meta_value END ) as _billing_address_1,
max( CASE WHEN pm.meta_key = '_billing_address_2' and p.ID = pm.post_id THEN pm.meta_value END ) as _billing_address_2,
max( CASE WHEN pm.meta_key = '_billing_city' and p.ID = pm.post_id THEN pm.meta_value END ) as _billing_city,
max( CASE WHEN pm.meta_key = '_billing_state' and p.ID = pm.post_id THEN pm.meta_value END ) as _billing_state,
max( CASE WHEN pm.meta_key = '_billing_postcode' and p.ID = pm.post_id THEN pm.meta_value END ) as _billing_postcode,
max( CASE WHEN pm.meta_key = '_shipping_first_name' and p.ID = pm.post_id THEN pm.meta_value END ) as _shipping_first_name,
max( CASE WHEN pm.meta_key = '_shipping_last_name' and p.ID = pm.post_id THEN pm.meta_value END ) as _shipping_last_name,
max( CASE WHEN pm.meta_key = '_shipping_address_1' and p.ID = pm.post_id THEN pm.meta_value END ) as _shipping_address_1,
max( CASE WHEN pm.meta_key = '_shipping_address_2' and p.ID = pm.post_id THEN pm.meta_value END ) as _shipping_address_2,
max( CASE WHEN pm.meta_key = '_shipping_city' and p.ID = pm.post_id THEN pm.meta_value END ) as _shipping_city,
max( CASE WHEN pm.meta_key = '_shipping_state' and p.ID = pm.post_id THEN pm.meta_value END ) as _shipping_state,
max( CASE WHEN pm.meta_key = '_shipping_postcode' and p.ID = pm.post_id THEN pm.meta_value END ) as _shipping_postcode,
max( CASE WHEN pm.meta_key = '_order_total' and p.ID = pm.post_id THEN pm.meta_value END ) as order_total,
max( CASE WHEN pm.meta_key = '_order_tax' and p.ID = pm.post_id THEN pm.meta_value END ) as order_tax,
max( CASE WHEN pm.meta_key = '_paid_date' and p.ID = pm.post_id THEN pm.meta_value END ) as paid_date,
( select group_concat( order_item_name separator '|' ) from wp_woocommerce_order_items where order_id = p.ID ) as order_items
from
wp_posts p 
join wp_postmeta pm on p.ID = pm.post_id
join wp_woocommerce_order_items oi on p.ID = oi.order_id
join wp_wc_order_coupon_lookup ocl on oi.order_id = ocl.order_id
where
p.ID IN (SELECT order_id FROM `wp_wc_order_coupon_lookup`)
group by
p.ID