SQL ROLLUP 与 COALESCE

Question

数据：

CREATE TABLE [dbo].[Purchase_Items]
(
    [ID] [int] NULL,
    [Model_Name] [varchar](50) NULL,
    [Brand] [varchar](50) NULL,
    [Price] [decimal](18, 2) NULL,
    [PurchaseDate] [date] NULL
);

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (1, N'Galaxy S10', N'Samsung', CAST(25000.00 AS Decimal(18, 2)), CAST(N'2020-01-12' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (2, N'Galaxy S20', N'Samsung', CAST(55000.00 AS Decimal(18, 2)), CAST(N'2020-01-18' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (3, N'Galaxy Note10', N'Samsung', CAST(40000.00 AS Decimal(18, 2)), CAST(N'2020-01-22' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (4, N'Galaxy A51', N'Samsung', CAST(21000.00 AS Decimal(18, 2)), CAST(N'2020-01-31' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (5, N'iPhone X', N'Apple', CAST(50000.00 AS Decimal(18, 2)), CAST(N'2020-02-03' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (6, N'iPhone 11', N'Apple', CAST(70000.00 AS Decimal(18, 2)), CAST(N'2020-02-07' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (7, N'iPhone 6s', N'Apple', CAST(20000.00 AS Decimal(18, 2)), CAST(N'2020-02-10' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (8, N'iPhone 8', N'Apple', CAST(30000.00 AS Decimal(18, 2)), CAST(N'2020-02-21' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (9, N'Y8', N'Huawei', CAST(16000.00 AS Decimal(18, 2)), CAST(N'2020-03-10' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (10, N'P30', N'Huawei', CAST(45000.00 AS Decimal(18, 2)), CAST(N'2020-03-12' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (11, N'Y9', N'Huawei', CAST(24000.00 AS Decimal(18, 2)), CAST(N'2020-03-14' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (12, N'P40', N'Huawei', CAST(50000.00 AS Decimal(18, 2)), CAST(N'2020-03-19' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (13, N'Redmi 9', N'Xiaomi', CAST(10000.00 AS Decimal(18, 2)), CAST(N'2020-03-21' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (14, N'Redmi K30', N'Xiaomi', CAST(25000.00 AS Decimal(18, 2)), CAST(N'2020-04-03' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (15, N'Mi Note 10', N'Xiaomi', CAST(15000.00 AS Decimal(18, 2)), CAST(N'2020-04-21' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (16, N'BlackShark', N'Xiaomi', CAST(30000.00 AS Decimal(18, 2)), CAST(N'2020-04-20' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (17, N'iPhone 11', N'Apple', CAST(70000.00 AS Decimal(18, 2)), CAST(N'2020-04-22' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (18, N'iPhone 11', N'Apple', CAST(70000.00 AS Decimal(18, 2)), CAST(N'2020-05-03' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (19, N'Galaxy S20', N'Samsung', CAST(55000.00 AS Decimal(18, 2)), CAST(N'2020-05-10' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (20, N'Galaxy S10', N'Samsung', CAST(25000.00 AS Decimal(18, 2)), CAST(N'2020-05-12' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (21, N'Galaxy Note10', N'Samsung', CAST(40000.00 AS Decimal(18, 2)), CAST(N'2020-05-14' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (22, N'iPhone 8', N'Apple', CAST(30000.00 AS Decimal(18, 2)), CAST(N'2020-05-21' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (23, N'BlackShark 3', N'Xiaomi', CAST(30000.00 AS Decimal(18, 2)), CAST(N'2020-05-22' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (24, N'P40', N'Huawei', CAST(45000.00 AS Decimal(18, 2)), CAST(N'2020-05-08' AS Date));

INSERT INTO [dbo].[Purchase_Items] ([ID], [Model_Name], [Brand], [Price], [PurchaseDate]) 
VALUES (25, N'iPhone X', N'Apple', CAST(70000.00 AS Decimal(18, 2)), CAST(N'2020-05-10' AS Date));

查询：

SELECT 
    MONTH(PurchaseDate) AS Months, 
    COALESCE(Brand, 'Monthly Total') AS 'Brand', 
    SUM(Price) AS TotalAmount 
FROM 
    Purchase_Items 
GROUP BY 
    ROLLUP(PurchaseDate, Brand);

我得到的输出是这样的：

它为每个未分组的单独品牌项目提供 null，我希望最后一个 null 为 'Grand Total' 而不是 'Monthly Total'。我尝试将 PurchaseDate 或 Brand 列放入和取出 ROLLUP，但它似乎不适用于要分组的品牌。

我想要的输出是这样的。计算每个品牌和每个月购买的所有商品，以及我之前提到的所有日期的所有购买商品的总计

Answer 1

只需在 ROLLUP 状态下使用 MONTH(PurchaseDate)：

SELECT 
    MONTH(PurchaseDate) AS Months, 
    COALESCE(Brand, 'Monthly Total') AS 'Brand', 
    SUM(Price) AS TotalAmount 
FROM 
    Purchase_Items 
GROUP BY 
    ROLLUP(MONTH(PurchaseDate), Brand);

Answer 2

这可以使用带有 GROUPING 的 CASE WHEN 结构来完成，如下所示：

SELECT 
    MONTH(PurchaseDate) AS Months, 
    CASE WHEN GROUPING(Brand) = 0 THEN Brand 
         When GROUPING(MONTH(PurchaseDate)) = 1 THEN 'Grand Total' 
         When GROUPING(Brand) = 1 THEN 'Monthly Total' END AS 'Brand',
    SUM(Price) AS TotalAmount 
FROM 
    Purchase_Items 
GROUP BY MONTH(PurchaseDate), Brand WITH ROLLUP;

SQL ROLLUP 与 COALESCE

SQL ROLLUP with COALESCE

sql

sql-server

rollup

coalesce