Puede usar esta consulta de MySQL para obtener todos los Cupones:
SELECT * FROM `wp_posts` WHERE `post_type` = 'shop_coupon' ORDER BY `ID` DESC
Y esto obtiene todos los cupones
SELECT p.`ID`,
p.`post_title` AS coupon_code,
p.`post_excerpt` AS coupon_description,
Max(CASE WHEN pm.meta_key = 'discount_type' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS discount_type, -- 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 = 'free_shipping' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS free_shipping, -- Allow free shipping
Max(CASE WHEN pm.meta_key = 'expiry_date' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS expiry_date, -- Coupon expiry date
Max(CASE WHEN pm.meta_key = 'minimum_amount' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS minimum_amount, -- Minimum spend
Max(CASE WHEN pm.meta_key = 'maximum_amount' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS maximum_amount, -- Maximum spend
Max(CASE WHEN pm.meta_key = 'individual_use' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS individual_use, -- Individual use only
Max(CASE WHEN pm.meta_key = 'exclude_sale_items' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS exclude_sale_items, -- Exclude sale items
Max(CASE WHEN pm.meta_key = 'product_ids' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS product_ids, -- Products
Max(CASE WHEN pm.meta_key = 'exclude_product_ids'AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS exclude_product_ids, -- Exclude products
Max(CASE WHEN pm.meta_key = 'product_categories' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS product_categories, -- Product categories
Max(CASE WHEN pm.meta_key = 'exclude_product_categories' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS exclude_product_categories,-- Exclude Product categories
Max(CASE WHEN pm.meta_key = 'customer_email' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS customer_email, -- Email restrictions
Max(CASE WHEN pm.meta_key = 'usage_limit' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS usage_limit, -- Usage limit per coupon
Max(CASE WHEN pm.meta_key = 'usage_limit_per_user' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS usage_limit_per_user, -- Usage limit per user
Max(CASE WHEN pm.meta_key = 'usage_count' AND p.`ID` = pm.`post_id` THEN pm.`meta_value` END) AS total_usaged -- Usage count
FROM `wp_posts` AS p
INNER JOIN `wp_postmeta` AS pm ON p.`ID` = pm.`post_id`
WHERE p.`post_type` = 'shop_coupon'
AND p.`post_status` = 'publish'
GROUP BY p.`ID`
ORDER BY p.`ID` ASC;
Referencia:Consulta MySQL para obtener todos los cupones
