q11.sql

WITH year_total AS (
  SELECT
    c_customer_id customer_id,
    c_first_name customer_first_name,
    c_last_name customer_last_name,
    c_preferred_cust_flag customer_preferred_cust_flag,
    c_birth_country customer_birth_country,
    c_login customer_login,
    c_email_address customer_email_address,
    d_year dyear,
    sum(ss_ext_list_price - ss_ext_discount_amt) year_total,
    's' sale_type
  FROM customer, store_sales, date_dim
  WHERE c_customer_sk = ss_customer_sk
    AND ss_sold_date_sk = d_date_sk
  GROUP BY c_customer_id
    , c_first_name
    , c_last_name
    , d_year
    , c_preferred_cust_flag
    , c_birth_country
    , c_login
    , c_email_address
    , d_year
  UNION ALL
  SELECT
    c_customer_id customer_id,
    c_first_name customer_first_name,
    c_last_name customer_last_name,
    c_preferred_cust_flag customer_preferred_cust_flag,
    c_birth_country customer_birth_country,
    c_login customer_login,
    c_email_address customer_email_address,
    d_year dyear,
    sum(ws_ext_list_price - ws_ext_discount_amt) year_total,
    'w' sale_type
  FROM customer, web_sales, date_dim
  WHERE c_customer_sk = ws_bill_customer_sk
    AND ws_sold_date_sk = d_date_sk
  GROUP BY
    c_customer_id, c_first_name, c_last_name, c_preferred_cust_flag, c_birth_country,
    c_login, c_email_address, d_year)
SELECT t_s_secyear.customer_preferred_cust_flag
FROM year_total t_s_firstyear
  , year_total t_s_secyear
  , year_total t_w_firstyear
  , year_total t_w_secyear
WHERE t_s_secyear.customer_id = t_s_firstyear.customer_id
  AND t_s_firstyear.customer_id = t_w_secyear.customer_id
  AND t_s_firstyear.customer_id = t_w_firstyear.customer_id
  AND t_s_firstyear.sale_type = 's'
  AND t_w_firstyear.sale_type = 'w'
  AND t_s_secyear.sale_type = 's'
  AND t_w_secyear.sale_type = 'w'
  AND t_s_firstyear.dyear = 2001
  AND t_s_secyear.dyear = 2001 + 1
  AND t_w_firstyear.dyear = 2001
  AND t_w_secyear.dyear = 2001 + 1
  AND t_s_firstyear.year_total > 0
  AND t_w_firstyear.year_total > 0
  AND CASE WHEN t_w_firstyear.year_total > 0
  THEN t_w_secyear.year_total / t_w_firstyear.year_total
      ELSE NULL END
  > CASE WHEN t_s_firstyear.year_total > 0
  THEN t_s_secyear.year_total / t_s_firstyear.year_total
    ELSE NULL END
ORDER BY t_s_secyear.customer_preferred_cust_flag
LIMIT 100;