productxxx.sql

SELECT history.*, history1.id AS h_id, (history1.retail_price - history.retail_price) AS t_price FROM product_price_histories AS history
      LEFT JOIN product_price_histories AS history1 ON history1.product_id = history.product_id
      LEFT JOIN products AS sku ON sku.id = history.product_id
      LEFT JOIN standard_products AS spu ON spu.id = sku.standard_product_id
      WHERE NOT EXISTS (
        SELECT t_h.id, t_h.created_at FROM product_price_histories AS t_h
        WHERE t_h.id != history.id
        AND t_h.product_id = history.product_id
        AND t_h.created_at >= '2016-03-29 08:28:54'
        AND t_h.created_at > history.created_at
      )
      AND (history.created_at >= '2016-03-29 08:28:54' AND history1.created_at >= '2016-03-29 08:28:54')
      AND (history.retail_price < history1.retail_price) AND (history.created_at > history1.created_at)
      GROUP BY history.product_id;