根据与其同一行的另一列更改列中的字符串值

Question

我想更改列中值的名称，该值将基于同一行中另一列中的值。

我正在使用 GROUP BY 运算符，使用 CUBE 关键字。

这是我用来创建 table:

的代码

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 [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 [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 [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 [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 [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 [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 [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 [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 [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 [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 [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 [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 [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));

这是我的查询：

SELECT month(PurchaseDate) Month,
   CASE WHEN month(PurchaseDate) is null then CONCAT('Grand Total for ', Brand) 
          ELSE COALESCE(Brand, 'Monthly Subtotal') end AS Brand,
   SUM(Price) as 'Total Amount'
FROM Purchase_Items
GROUP BY CUBE(month(PurchaseDate), Brand)

这是输出：

Purchase Month   |         Brand           | Total Amount
---------------------------------------------------------
        3        |         Xiaomi          |   10000.00 
        4        |         Xiaomi          |   70000.00
        5        |         Xiaomi          |   30000.00
       NULL      |  Grand Total for Xiaomi |  110000.00
        2        |         Apple           |  170000.00
        4        |         Apple           |   70000.00
        5        |         Apple           |  170000.00
       NULL      |  Grand Total for Apple  |  410000.00           
       NULL      |    Grand Total for      |  520000.00
        1        |     Monthly Subtotal    |  250000.00
        2        |     Monthly Subtotal    |  200000.00
        3        |     Monthly Subtotal    |   70000.00

我想将 'Grand Total for' 更改为 'Grand Total'，但我不知道如何更改。

我在想是否可以根据 'Total Amount' 列中的最高数字更改它，因为它们共享同一行，但也许还有其他方法可以解决这个问题。

我该如何解决这个问题？

Answer 1

测试类似

CASE WHEN month(PurchaseDate) IS NULL AND Brand IS NULL THEN 'Grand Total'
     WHEN month(PurchaseDate) IS NULL                   THEN CONCAT('Grand Total for ', Brand) 
                                                        ELSE COALESCE(Brand, 'Monthly Subtotal') 
     END AS Brand,

第一种情况 - 也许 WHEN Brand IS NULL 就足够了？

根据与其同一行的另一列更改列中的字符串值

Change the string value in a column based on another column that is the same row with it

sql-server

group-by

coalesce

case-when