SQL Group BY, Top N Items for each Group

问题:

I have a SQL Query which gets gets top 5 sold items at a given store.

SELECT TOP 5 S.UPCCode, SUM(TotalDollarSales) FROM Sales S WHERE S.StoreId = 1 GROUP BY S.UPCCode ORDER BY SUM(S.TotalDollarSales) desc 

The Sales table has -> UPCCode, SaleDate, StoreId, TotalDollarSales

I am looking for a query which will return me Top 5 items sold for each of the stores in a single query. I can write multiple queries and use a union but it doesn't seem efficient.

How can I get the top 5 sold items for each store in a single query.

Thanks in advance.

回答1:

;WITH s AS  (   SELECT StoreID, UPCCode, tds, rn = ROW_NUMBER()   OVER (PARTITION BY StoreID ORDER BY tds DESC)   FROM    (     SELECT StoreID, UPCCode, tds = SUM(TotalDollarSales)     FROM Sales     GROUP BY StoreID, UPCCode   ) AS s2 ) SELECT StoreID, UPCCode, TotalDollarSales = tds FROM s WHERE rn 5 ORDER BY StoreID, TotalDollarSales DESC; 

回答2:

try this:

select ss.StoreId,is.* from (select distinct StoreId from Sales) ss cross apply (SELECT TOP 5 S.UPCCode, SUM(TotalDollarSales) as SumTotalDollarSales FROM Sales S              WHERE S.StoreId = ss.StoreId              GROUP BY S.UPCCode              ORDER BY SUM(S.TotalDollarSales) desc) is 

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