次のような約12000個のアイテムになる複雑な結合クエリがあります
SELECT a.ID AS 'DealID', a.TradeDate, c.COMPANYNAME AS 'Seller Company', a.SellCommission, h.BROKER_FULLNAME AS 'Seller Trader',
j.DisplayName AS 'Seller Broker', d.COMPANYNAME AS 'Buyer Company', a.BuyCommission, g.BROKER_FULLNAME AS 'Buyer Trader',
i.DisplayName AS 'Buyer Broker', e.PRODUCT_NAME, f.TYPE_DESC AS 'Quantity Type', f.NBR_OF_GALLONS AS 'Quantity Multiplier', a.ContractVolume,
a.TotalVolume, a.DeliveryPoint, a.Price, a.ContractStart, a.ContractEnd
FROM Confirmations AS a WITH (nolock) LEFT OUTER JOIN
COMPANY AS c WITH (nolock) ON c.COMPANY_ID = a.SellCompany LEFT OUTER JOIN
COMPANY AS d WITH (nolock) ON d.COMPANY_ID = a.BuyCompany LEFT OUTER JOIN
BIOPRODUCTTYPES AS e WITH (nolock) ON e.ID = a.ProductID LEFT OUTER JOIN
BIO_QUANTITY_TYPE AS f WITH (nolock) ON f.ID = a.QuantityTypeID LEFT OUTER JOIN
COMPANYBROKER AS g WITH (nolock) ON g.COMPANYBROKER_ID = a.BuyTrader LEFT OUTER JOIN
COMPANYBROKER AS h WITH (nolock) ON h.COMPANYBROKER_ID = a.SellTrader LEFT OUTER JOIN
Users AS i WITH (nolock) ON i.ID = a.BuyBroker LEFT OUTER JOIN
Users AS j WITH (nolock) ON j.ID = a.SellBroker
WHERE (a.TradeDate >= '2011-04-01 00:00:00') AND (a.TradeDate <= '2013-10-25 00:00:00')
ORDER BY a.TradeDate
しかし、すべての 12000 レコードの代わりに、「Seller Trader」ごとに最新のレコードである 1 つのレコードが必要です (現在、上記のクエリは、売り手トレーダーによって行われたすべての取引を返します)。これは、おそらく約 300 レコードを返します。