sorting - 如何按汇总组排序？

Question

假设我在 SQL Server 2008 R2 中有一个Purchase用两列调用的表：Purchaser和 Expenditure.

假设该表具有以下行：

Purchaser    Expenditure
---------    -----------
Alex         200
Alex         300
Alex         500
Bob          300
Bob          400
Charlie      200
Charlie      600
Derek        100
Derek        300

现在我有这个查询：

SELECT Purchaser, Expenditure, SUM(Expenditure) AS SumExpenditure FROM Purchase GROUP BY Purchaser, Expenditure WITH ROLLUP

这将返回以下内容：

Purchaser    Expenditure    SumExpenditure
---------    -----------    --------------
Alex         200            200
Alex         300            300
Alex         500            500
--------------------------------
Alex         NULL           1000
--------------------------------
Bob          300            300
Bob          400            400
--------------------------------
Bob          NULL           700
--------------------------------
Charlie      200            200
Charlie      600            600
--------------------------------
Charlie      NULL           800
--------------------------------
Derek        100            100
Derek        300            300
--------------------------------
Derek        NULL           400
--------------------------------

（添加线条以强调汇总的金额。）

我希望能够按分组数量对组进行排序，以便最终得到如下结果集：

Purchaser    Expenditure    SumExpenditure
---------    -----------    --------------
Derek        100            100
Derek        300            300
--------------------------------
Derek        NULL           400
--------------------------------
Bob          300            300
Bob          400            400
--------------------------------
Bob          NULL           700
--------------------------------
Charlie      200            200
Charlie      600            600
--------------------------------
Charlie      NULL           800
--------------------------------
Alex         200            200
Alex         300            300
Alex         500            500
--------------------------------
Alex         NULL           1000
--------------------------------

换句话说，我正在对组进行排序，使用,400和在组行中按升序排列。7008001000

谁能建议什么查询会返回这个结果集？

Answer 1

;WITH x AS 
(
    SELECT Purchaser, Expenditure, s = SUM(Expenditure) 
    FROM dbo.Purchase 
    GROUP BY Purchaser, Expenditure WITH ROLLUP
),
y AS 
(
    SELECT Purchaser, s FROM x 
    WHERE Expenditure IS NULL
    AND Purchaser IS NOT NULL
),
z AS 
(
    SELECT Purchaser, s, rn = ROW_NUMBER() OVER (ORDER BY s)
    FROM y
)
SELECT x.Purchaser, x.Expenditure, x.s FROM x 
INNER JOIN z ON x.Purchaser = z.Purchaser
ORDER BY z.rn, CASE WHEN z.s IS NULL THEN 2 ELSE 1 END;