SQL：同じテーブルの4つの「where」節を組み合わせる

Question

現在、これを動作させるのに苦労しています。

SELECT  Y, SUM(N) AS sumDK, NULL AS sumFI, NULL AS sumNO, NULL AS sumSE 
FROM   stat 
WHERE  (C = 'Denmark') 
GROUP BY Y 
UNION ALL 
SELECT  Y, NULL AS sumDK, SUM(N) AS sumFI, NULL AS sumNO, NULL AS sumSE 
FROM   stat 
WHERE  (C = 'Finland') 
GROUP BY Y 
UNION ALL 
SELECT  Y, NULL AS sumDK, NULL AS sumFI, SUM(N) AS sumNO, NULL AS sumSE 
FROM   stat 
WHERE  (C = 'Norway') 
GROUP BY Y 
UNION ALL 
SELECT  Y, NULL AS sumDK, NULL AS sumFI, NULL AS sumNO, SUM(N) AS sumSE 
FROM   stat 
WHERE  (C = 'Sweden') 
GROUP BY Y 

このクエリは、私にこのような行列を与える：

Y | sumDK | sumFI | sumNO | sumSE 
---------------------------------- 
2011| 25 | NULL | NULL | NULL 
2012| 5 | NULL | NULL | NULL 
2011| NULL | 18 | NULL |NULL 
2012| NULL | 5 | NULL |NULL 
...... 

にはどうすればいいだけのNOT NULLフィールドを返すクエリを実行することができますか？ ありがとうございます！

Answer 1

について一度テーブルを通過し、各列

select 
     Y, 
     SUM(IIF(C = 'Denmark', N, 0)) as SumDenmark, 
     SUM(IIF(C = 'Finland', N, 0)) as SumFinland, 
     SUM(IIF(C = 'Norway', N, 0)) as SumNorway, 
     SUM(IIF(C = 'Sweden', N, 0)) as SumSweden, 
     sum(N) totalSumValue, 
     count(*) totalEntries 
    FROM 
     STAT 
    WHERE 
     C IN ('Denmark', 'Finland', 'Norway', 'Sweden') 
    GROUP BY 
     Y 

Answer 2

すべての名前を変更する必要はありますか？何

SELECT  Y, SUM(N) AS sum, C 
FROM   stat 
WHERE  (C = 'Denmark') 
GROUP BY Y 
UNION ALL 
SELECT  Y, SUM(N) AS sum, C 
FROM   stat 
WHERE  (C = 'Finland') 
GROUP BY Y 
UNION ALL 
SELECT  Y, SUM(N) AS sum, C 
FROM   stat 
WHERE  (C = 'Norway') 
GROUP BY Y 
UNION ALL 
SELECT  Y, SUM(N) AS sum, C 
FROM   stat 
WHERE  (C = 'Sweden') 
GROUP BY Y 

Answer 3

SELECT  Y, C, SUM(N) 'Sum' 
FROM  stat 
WHERE  C IN ('Denmark', 'Finland', 'Norway', 'Sweden') 
GROUP BY Y, C 

Answer 4

ベストの推測の試合を加算することにより、クロスタブとして、それを作成する - 私は便利なアクセスを持っていません試してみるTRANSFORM：

TRANSFORM SUM(N) 
    SELECT Y FROM STAT 
    GROUP BY Y 
    ORDER BY Y 
    PIVOT C