TOP_5.sql

  SELECT sum(total * 1), r.merchant
    FROM summaries s
    JOIN retailers r
      ON s.retailer_id = r.id
    JOIN (
    SELECT sum(total) top_5_total, r.merchant AS top_5_merchant
      FROM summaries s
      JOIN retailers r
        ON s.retailer_id = r.id
     WHERE item_date >= '2007-01-01'
       AND item_date <= '2009-12-31'
       AND CASE 0
           WHEN 0 THEN 1=1
           ELSE account_id IN (SELECT id FROM accounts WHERE partner_id = 0) END
     GROUP BY merchant
     ORDER BY sum(total) DESC
     LIMIT 5 ) top_5
      ON r.merchant = top_5.top_5_merchant
   WHERE item_date >= '2007-01-01'
     AND item_date <= '2009-12-31'
     AND CASE 0
    WHEN 0 THEN 1=1
    ELSE account_id IN (SELECT id FROM accounts WHERE partner_id = 0) END
   GROUP BY merchant
   ORDER BY merchant, total