SQL Group by 和更新/删除行

Question

我有一个 SQL.Table

CREATE TABLE [dbo].[Stack_Example](
    [ID] [bigint] NOT NULL,
    [Product_ID] [bigint] NULL,
    [Quantity] [decimal](18, 2) NULL,
    [Price] [decimal](18, 2) NULL,
 CONSTRAINT [PK_Stack_Example] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

数据如下所示：

INSERT [dbo].[Stack_Example] ([ID], [Product_ID], [Quantity], [Price]) VALUES (1, 25, CAST(55.00 AS Decimal(18, 2)), CAST(1000.00 AS Decimal(18, 2)))
GO
INSERT [dbo].[Stack_Example] ([ID], [Product_ID], [Quantity], [Price]) VALUES (2, 25, CAST(1.00 AS Decimal(18, 2)), CAST(1000.00 AS Decimal(18, 2)))
GO
INSERT [dbo].[Stack_Example] ([ID], [Product_ID], [Quantity], [Price]) VALUES (3, 26, CAST(1.00 AS Decimal(18, 2)), CAST(500.00 AS Decimal(18, 2)))
GO

所以我的问题是我需要按价格、产品 ID 和总和（数量）对这些项目进行分组。

假设我的输出窗口需要看起来像这样，则需要更新/删除查询

选择查询很简单

select Product_ID,SUM(Quantity) AS Quantity,Price from Stack_Example
Group by Product_ID,Price

所以一开始我需要做的是删除 id 为 2 的行并更新 id 为 1 的行 set Quantity = Quantity + 1 ( Quantity of deleted row )。

所以当我运行选择查询而不分组和求和时，我需要得到相同的输出

UPDATE Stack_Example SET Quantity = (SELECT SUM(Quantity)
                                    FROM Stack_Example child 
                                    WHERE child.Product_ID = Stack_Example.Product_ID
                                    GROUP BY Product_ID)

DELETE FROM Stack_Example WHERE ID IN (SELECT TOP 1 ID 
                                        FROM Stack_Example 
                                        WHERE Product_Id IN ( (SELECT TOP 1 Product_ID 
                                                                    FROM Stack_Example
                                                                    GROUP BY Product_ID 
                                                                    HAVING COUNT(Product_ID)>1)))

Answer 1

首先用相同价格的产品总量更新您的表格

with cte as (
    select
        Product_ID, Price, Quantity = sum(Quantity) 
    from
        Stack_Example
    group by Product_ID, Price
)

update s
set s.Quantity = c.Quantity
from
    Stack_Example s
    join cte c on s.Product_ID = c.Product_ID and s.Price = c.Price

然后运行另一个脚本来删除重复的行

with cte as (
    select
        *, row_number() over (partition by Product_ID, Price order by Product_ID) rn
    from
        Stack_Example
)

delete from cte where rn > 1

Answer 2

我有点不清楚 - 但你不能只用聚合创建一个视图吗？

无论如何...... 不知道你为什么要这样做，但是......你可以插入聚合值，然后删除旧的......如下所示。

DECLARE @MaxId INT;
DECLARE @ProductId = 25;


--GET THE MAX ID OF PRODUCT IN QUESTION
SELECT @MaxId = MAX(ID) FROM Stack_Example WHERE Product_Id = @ProductId;


--INSERT THE AGGREGATE VALUES INTO TABLE
INSERT INTO Stack_Example
  SELECT @MaxId + 1, @ProductId, Price, SUM(Quantity)
  FROM Stack_Example
  WHERE 
    Product_Id = @ProductId
  GROUP BY 
    @MaxId + 1, [Product_ID], [Price];

--DELETE THE PRE-AGGREGATE VALUES
DELETE FROM Stack_Example WHERE ProductId = @ProductId and Id <= @MaxId;

Answer 3

嗯，我使用了聚合和额外的临时表来实现这一点：

--group records and insert them into temporary table
select distinct
     Min(id) over (partition by product_id, price) [ID],
     Product_id,
     sum(Quantity) over (partition by product_id, price) [Quantity],
     Price
into #new_stack_example
from #Stack_Example

--delete old values
delete #Stack_example

--insert new values
insert into #Stack_example
select * from #new_stack_example

第一个SELECT 语句反映了您的逻辑：

所以我的问题是我需要按价格、产品 ID 和总和（数量）对这些项目进行分组。

但我没有分组，而是使用窗口函数，然后选择不同的记录。

Answer 4

检查这个：

    UPDATE Stack_Example SET Quantity = a.Quantity
    from ( select Product_ID,sum(Quantity) Quantity  
    from Stack_Example Group by Product_ID) a
    where   Stack_Example.Product_ID=a.Product_ID   

    ;with cte as (
    select *,ROW_NUMBER () over (partition by product_id order by product_id) rn 
    from Stack_Example)

    delete from cte where rn > 1