gns. salg af kvartal med forrige kvartal gns. salg

Redigeret med de seneste krav.

Dit problem er, at du forsøger at få forrige_avg ved at forsøge at manipulere QTR og YEAR. Jeg bruger RANK-funktionen og bestiller, som jeg vil have dataene rangeret. I sammenføjningerne sørger jeg for, at gennemsnitlig region =forrige region, og hvis man ser bort fra år siden det foregående kvartal, kan det være 4. kvartal af det foregående år for gennemsnitsår 1. kvartal; det er renere på denne måde.

    --Build the test table
    IF OBJECT_ID('SALES','U') IS NOT NULL
        DROP TABLE SALES

    CREATE TABLE SALES
    (
          Region  VARCHAR(255)
        , Product VARCHAR(10)
        , [Year]  INT
        , QTR     INT
        , [Month] VARCHAR(19)
        , Sales   DECIMAL(19,4)
    );

    INSERT SALES
    VALUES
         ('NORTH', 'P1', 2015, 1, 'JAN', 1000)
        ,('NORTH', 'P1', 2015, 1, 'FEB', 2000)
        ,('NORTH', 'P1', 2015, 1, 'MAR', 3000)
        ,('NORTH', 'P1', 2015, 2, 'APR', 4000)
        ,('NORTH', 'P1', 2015, 2, 'MAY', 5000)
        ,('NORTH', 'P1', 2015, 2, 'JUN', 6000)
        ,('NORTH', 'P1', 2015, 3, 'JUL', 7000)
        ,('NORTH', 'P1', 2015, 3, 'AUG', 8000)
        ,('NORTH', 'P1', 2015, 3, 'SEP', 9000)
        ,('NORTH', 'P1', 2015, 4, 'OCT', 1000)
        ,('NORTH', 'P1', 2015, 4, 'DEC', 4000)
        ,('NORTH', 'P1', 2015, 4, 'NOV', 2000)
        ,('NORTH', 'P3', 2015, 1, 'FEB', 1000)
        ,('NORTH', 'P3', 2015, 1, 'FEB', 9000)
        ,('NORTH', 'P3', 2015, 2, 'APR', 2000)
        ,('NORTH', 'P3', 2015, 3, 'JUL', 8000)
        ,('NORTH', 'P1', 2016, 1, 'MAR', 3000)
        ,('NORTH', 'P1', 2016, 1, 'FEB', 1000)
        ,('NORTH', 'P1', 2016, 1, 'JAN', 2000)
        ,('SOUTH', 'P1', 2015, 1, 'JAN', 2000)
        ,('SOUTH', 'P1', 2015, 1, 'FEB', 3000)
        ,('SOUTH', 'P1', 2015, 1, 'JAN', 4000)
        ,('SOUTH', 'P2', 2015, 1, 'MAR', 1000)
        ,('SOUTH', 'P2', 2015, 1, 'JAN', 8000)
        ,('SOUTH', 'P2', 2015, 1, 'FEB', 9000)
        ,('SOUTH', 'P2', 2015, 2, 'JUN', 9000)
        ,('SOUTH', 'P2', 2015, 2, 'MAY', 8000)
        ,('SOUTH', 'P2', 2015, 2, 'APR', 2000)
        ,('SOUTH', 'P2', 2015, 3, 'SEP', 4000)
        ,('SOUTH', 'P2', 2015, 3, 'AUG', 2000)
        ,('SOUTH', 'P2', 2015, 3, 'JUL', 1000)
        ,('SOUTH', 'P2', 2015, 4, 'NOV', 2000)
        ,('SOUTH', 'P2', 2015, 4, 'DEC', 1000)
        ,('SOUTH', 'P2', 2015, 4, 'OCT', 5000)
        ,('SOUTH', 'P3', 2015, 3, 'AUG', 9000)
        ,('SOUTH', 'P3', 2015, 4, 'OCT', 1000)
        ,('SOUTH', 'P3', 2015, 4, 'NOV', 3000)
        ,('SOUTH', 'P2', 2016, 1, 'JAN', 2000)
        ,('SOUTH', 'P2', 2016, 1, 'JAN', 4000);


    --CTE TO CAPTURE AVG SALES BY REGION, PRODCUT, YEAR, QTR;  OMIT PRODUCT IF YOU WANT STRAIGHT UP QUARTER AVG, REGARDLESS OF PRODCUCT
    WITH cteAvgSales AS
    (
        SELECT Region, Product, [Year], QTR, AVG(Sales) current_avg
            , RANK() OVER(ORDER BY Region, Product, [Year], QTR) AS RNK
        FROM SALES
        GROUP BY Region, Product, [Year], QTR
    )
    SELECT s.Region, s.Product, s.[Year] AS [year], s.QTR AS [quarter], s.[Month], s.Sales, a.current_avg, p.current_avg AS previous_avg
    FROM SALES s
        INNER JOIN cteAvgSales a ON a.Region = s.Region
            AND a.Product = s.Product
            AND a.[Year]  = s.[Year]
            AND a.QTR = s.QTR
        LEFT JOIN cteAvgSales p ON p.Region = a.Region
            AND p.Product = s.Product
            AND p.RNK=a.RNK-1
    ORDER BY s.Region, s.Product, s.[Year], s.QTR