SQL：GROUPING SETS和PIVOT的替代和替代

Question

我有這樣的代碼：

SELECT id, YEAR(datek) AS YEAR, COUNT(*) AS NUM
FROM Orders
GROUP BY GROUPING SETS
(
    (id, YEAR(datek)),
    id,
    YEAR(datek),
    ()
);

它給了我這個輸出：

1   NULL    4
2   NULL    11
3   NULL    6
NULL    NULL    21
1   2006    36
2   2006    56
3   2006    51
NULL    2006    143
1   2007    130
2   2007    143
3   2007    125
NULL    2007    398
1   2008    79
2   2008    116
3   2008    73
NULL    2008    268
NULL    NULL    830
1   NULL    249
2   NULL    326
3   NULL    255

我需要做的是編寫沒有“分組集”（也不是多維數據集或匯總）但結果相同的代碼。 我考慮過編寫三個不同的查詢，然后將它們與“聯合”一起加入。 我在分組設置中嘗試了類似“ null”的操作，但是它不起作用。

SELECT id, YEAR(datek) AS rok, COUNT(*) AS NUM
FROM Orders
GROUP BY id, YEAR(datek)
UNION
SELECT id, YEAR(datek) AS rok, COUNT(*) AS NUM
FROM Orders
GROUP BY id, null
order by id, YEAR(datek)

我也有一個關於“ PIVOT”的問題。 什么樣的語法可以用“ PIVOT”代替查詢？

感謝您的時間和所有答案！

Answer 1

正確的是，盡管實際上需要4個查詢，但您需要單獨的查詢，而不是GROUP BY NULL ，僅按相應分組集中的列進行分組，然后將SELECT的列替換為NULL ：

SELECT id, YEAR(datek) AS rok, COUNT(*) AS NUM
FROM Orders
GROUP BY id, YEAR(datek)

UNION ALL

SELECT id, NULL, COUNT(*) AS NUM
FROM Orders
GROUP BY id

UNION ALL

SELECT NULL, YEAR(datek), COUNT(*) AS NUM
FROM Orders
GROUP BY YEAR(datek)

UNION ALL

SELECT NULL, NULL, COUNT(*) AS NUM
FROM Orders
ORDER BY ID, Rok

關於替代PIVOT我認為最好的替代方法是使用條件聚合，例如：

SELECT  pvt.SomeGroup,
        pvt.[A],
        pvt.[B],
        pvt.[C]
FROM    T
        PIVOT (SUM(Val) FOR Col IN ([A], [B], [C])) AS pvt;

您將使用：

SELECT  T.SomeGroup,
        [A] = SUM(CASE WHEN T.Col = 'A' THEN T.Val ELSE 0 END),
        [B] = SUM(CASE WHEN T.Col = 'B' THEN T.Val ELSE 0 END),
        [C] = SUM(CASE WHEN T.Col = 'C' THEN T.Val ELSE 0 END)
FROM    T
GROUP BY T.SomeGroup;