find-missing-order-posts.sql

-- Get the missing order post IDs
SELECT post_id as missing_order,
       -- "Estimate" the date by looking at the next available post's date
       ( 
           SELECT   post_date 
           FROM     wp_posts
           WHERE    ID > post_id
           ORDER BY ID ASC
           LIMIT    1
	   ) as nearest_date 

FROM wp_postmeta 

LEFT JOIN wp_posts
       ON wp_posts.ID = wp_postmeta.post_id

-- Order posts all have a _payment_method meta field
-- (indicating PayPal or Stripe, etc)
WHERE meta_key = '_payment_method'
  AND ID IS NULL