任何类别或子类别中的顶级品牌列表答案

【问题标题】：List of Top brands in any category or subcategory任何类别或子类别中的顶级品牌列表
【发布时间】：2012-06-11 02:54:26
【问题描述】：

我使用的是SQL Server 2008，我迫切需要sql查询或存储过程来显示任何类别或子类别中的顶级品牌。例如，如果我通过 IdCategory=2，结果集应该通过对 idCategory=2 及其子类别和子子类别执行产品计数来显示电子产品中的顶级品牌。如果我通过 IdCategory=38，结果应该会显示 Phones & Mobile Devices 以及 Mobile Phones 中的顶级品牌。我希望我能够清除我的要求。

这是我数据库中的表。

类别

IdCategory    CategoryName              ParentCategoryId
---------------------------------------------------------
1             Appliances                Null
2             Electronics               Null
38            Phones & Mobile Devices   2
39            Cameras & Photography     2
115           Mobile Phones             38
121           Digital Cameras           39

品牌

IdBrand       BrandName 
------------------------
1             Nokia
2             Samsung
3             Canon

下表打破了类别和品牌表之间的多对多关系

类别品牌

IdCategoriesBrand    IdCategory   IdBrand
-----------------------------------------
1                    2            1
2                    38           1
3                    115          1
4                    2            2
5                    38           2
6                    115          2

产品

IdProduct     Product Name       IdCategory    IdBrand
---------------------------------------------------------
1             AAAA               115           1
2             BBBB               115           2
3             CCCC               121           3
4             DDDD               115           1
5             EEEE               121           3

关于产品表的假设

产品只能添加到第三级子子类别中（例如手机、数码相机）

这里是创建表的脚本

CREATE TABLE [dbo].[Categories](
    [IdCategory] [bigint]  NOT NULL,
    [CategoryName] [nvarchar](50) NULL,  
    [ParentCategoryId] [bigint] NULL
    CONSTRAINT [PK_Categories_IdCategory] PRIMARY KEY CLUSTERED (   [IdCategory] ASC )
) ON [PRIMARY]

GO


CREATE TABLE [dbo].[Brands](
    [IdBrand] [bigint]  NOT NULL,
    [BrandName] [nvarchar](50) NULL
    CONSTRAINT [PK_Brands_IdBrand] PRIMARY KEY CLUSTERED (  [IdBrand] ASC )
) ON [PRIMARY]

GO

CREATE TABLE [dbo].[CategoriesBrands](
    [IdCategoriesBrand] [bigint]  NOT NULL,
    [IdCategory] [bigint] NULL,
    [IdBrand] [bigint] NULL,
    CONSTRAINT [PK_CategoriesBrands] PRIMARY KEY CLUSTERED (    [IdCategoriesBrand] ASC )
) ON [PRIMARY]

GO

ALTER TABLE [dbo].[CategoriesBrands]  WITH CHECK ADD  CONSTRAINT [FK_CategoriesBrands_Brands] FOREIGN KEY([IdBrand])
REFERENCES [dbo].[Brands] ([IdBrand])
GO

ALTER TABLE [dbo].[CategoriesBrands] CHECK CONSTRAINT [FK_CategoriesBrands_Brands]
GO

ALTER TABLE [dbo].[CategoriesBrands]  WITH CHECK ADD  CONSTRAINT [FK_CategoriesBrands_Categories] FOREIGN KEY([IdCategory])
REFERENCES [dbo].[Categories] ([IdCategory])
GO

ALTER TABLE [dbo].[CategoriesBrands] CHECK CONSTRAINT [FK_CategoriesBrands_Categories]
GO

CREATE TABLE [dbo].[Products](
    [IdProduct] [bigint]  NOT NULL,
    [ProductName] [nvarchar](200) NULL,
    [IdCategory] [bigint] NULL,
    [IdBrand] [bigint] NULL 
    CONSTRAINT [PK_Products_IdProduct] PRIMARY KEY CLUSTERED (  [IdProduct] ASC )
) ON [PRIMARY]

GO

ALTER TABLE [dbo].[Products]  WITH CHECK ADD  CONSTRAINT [FK_Products_Brands] FOREIGN KEY([IdBrand])
REFERENCES [dbo].[Brands] ([IdBrand])
GO

ALTER TABLE [dbo].[Products] CHECK CONSTRAINT [FK_Products_Brands]
GO

ALTER TABLE [dbo].[Products]  WITH CHECK ADD  CONSTRAINT [FK_Products_Categories] FOREIGN KEY([IdCategory])
REFERENCES [dbo].[Categories] ([IdCategory])
GO

ALTER TABLE [dbo].[Products] CHECK CONSTRAINT [FK_Products_Categories]
GO

这里是在表格中插入一些示例数据的脚本

INSERT INTO Categories (IdCategory, CategoryName, ParentCategoryId) VALUES(1, 'Appliances', NULL)
INSERT INTO Categories (IdCategory, CategoryName, ParentCategoryId) VALUES(2, 'Electronics', NULL)
INSERT INTO Categories (IdCategory, CategoryName, ParentCategoryId) VALUES(38, 'Phones & Mobile Devices', 2)
INSERT INTO Categories (IdCategory, CategoryName, ParentCategoryId) VALUES(39, 'Cameras & Photography', 2)
INSERT INTO Categories (IdCategory, CategoryName, ParentCategoryId) VALUES(115, 'Mobile Phones', 38)
INSERT INTO Categories (IdCategory, CategoryName, ParentCategoryId) VALUES(121, 'Digital Cameras', 39)


INSERT INTO Brands (IdBrand, BrandName) VALUES(1, 'Nokia')
INSERT INTO Brands (IdBrand, BrandName) VALUES(2, 'Samsung')
INSERT INTO Brands (IdBrand, BrandName) VALUES(3, 'Canon')


INSERT INTO CategoriesBrands (IdCategoriesBrand, IdCategory, IdBrand) VALUES(1, 2, 1)
INSERT INTO CategoriesBrands (IdCategoriesBrand, IdCategory, IdBrand) VALUES(2, 38, 1)
INSERT INTO CategoriesBrands (IdCategoriesBrand, IdCategory, IdBrand) VALUES(3, 115, 1)
INSERT INTO CategoriesBrands (IdCategoriesBrand, IdCategory, IdBrand) VALUES(4, 2, 2)
INSERT INTO CategoriesBrands (IdCategoriesBrand, IdCategory, IdBrand) VALUES(5, 38, 2)
INSERT INTO CategoriesBrands (IdCategoriesBrand, IdCategory, IdBrand) VALUES(6, 115, 2)


INSERT INTO Products (IdProduct, ProductName, IdCategory, IdBrand) VALUES(1, 'AAAA', 115, 1)
INSERT INTO Products (IdProduct, ProductName, IdCategory, IdBrand) VALUES(2, 'BBBB', 115, 2)
INSERT INTO Products (IdProduct, ProductName, IdCategory, IdBrand) VALUES(3, 'CCCC', 121, 3)
INSERT INTO Products (IdProduct, ProductName, IdCategory, IdBrand) VALUES(4, 'DDDD', 115, 1)
INSERT INTO Products (IdProduct, ProductName, IdCategory, IdBrand) VALUES(5, 'EEEE', 121, 3)

到目前为止，我已经尝试过这个，它给了我前 5 个没有类别的品牌

SELECT TOP 5
    b1.IdBrand, 
    ISNULL(b1.BrandName, '') AS BrandName, 
    count(p.IdProduct) AS 'ProductsCount'
FROM Brands b1
LEFT OUTER JOIN Products p
ON b1.IdBrand = p.IdBrand 
GROUP BY b1.IdBrand, b1.BrandName 
ORDER BY ProductsCount DESC

【问题讨论】：

它更像是您在此处委派的作业/家庭作业。
一些用于创建表和插入的脚本也会有所帮助 - 我只需要 Products 和 Categories 的脚本
不，这不是家庭作业/作业，实际上我创建了一个消费品评论网站并停留在此查询上。这是您询问的完整脚本。
我在您的表格中看不到任何销售或可靠性数据。如何确定顶级品牌？
在不久的将来，我将添加评论表，该表将根据评论确定顶级品牌。目前我想根据产品数量来确定。

标签： sql sql-server-2008 tsql

【解决方案1】：

这是我解决这个问题的尝试：

首先获取所有类别，从根目录开始（使用递归 CTE）
按 categoryId 计算品牌排名
对于每个类别，显示前 5 个品牌

我还制作了一个 SQLFiddle，您可以在其中玩弄查询：http://sqlfiddle.com/#!3/8593b/12

这是代码：

declare @IdCategory bigint

set @IdCategory = 2

declare @selectedCategories
  table (IdCategory bigint primary key)


-- Use a recursive CTE to determine all
-- Categories that derive from current
-- Category
;with SelectedCategories as (
  select @IdCategory as IdCategory
  union all
  select c.IdCategory 
    from Categories c
    join SelectedCategories sc
      on sc.IdCategory = c.ParentCategoryId
)
-- Save Selected Categories
-- in a memory table
insert @selectedCategories (IdCategory)
select IdCategory from SelectedCategories

-- use another CTE to select the 
-- Brands in the Selected Categories
-- and compute their Category rank
-- using the RANK()
;with BrandsPerCategory as (
  select 
    c.IdCategory,
    cc.CategoryName,
    b.BrandName,
    rank() over (
      partition by c.IdCategory
      order by count(p.IdProduct) desc
    ) as BrandRank
  from @selectedCategories c
  join Categories cc
    on c.IdCategory = cc.IdCategory
  join CategoriesBrands cb
    on cb.IdCategory = c.IdCategory
  join Brands b
    on cb.IdBrand = b.IdBrand
  join Products p
    on p.IdBrand = b.IdBrand
  group by 
    c.IdCategory,
    cc.CategoryName,
    b.BrandName
)
select * 
from BrandsPerCategory
where BrandRank < 5
order by IdCategory, BrandRank

编辑：

如果您想要所有选定类别（根+子类别）的顶级品牌，而不是上面示例中的每个类别，那么您可以使用以下查询（和thisSqlFiddle）：

declare @IdCategory bigint

set @IdCategory = 2

-- Use a recursive CTE to determine all
-- Categories that derive from current
-- Category
;with SelectedCategories as (
  select @IdCategory as IdCategory
  union all
  select c.IdCategory 
    from Categories c
    join SelectedCategories sc
      on sc.IdCategory = c.ParentCategoryId
)
select top 5
  b.IdBrand, 
  b.BrandName,
  count(p.IdProduct) AS 'ProductsCount'
from SelectedCategories c
join Categories cc
  on c.IdCategory = cc.IdCategory
join CategoriesBrands cb
  on cb.IdCategory = c.IdCategory
join Brands b
  on cb.IdBrand = b.IdBrand
join Products p
  on p.IdBrand = b.IdBrand
GROUP BY b.IdBrand, b.BrandName 
ORDER BY ProductsCount DESC

编辑2： （不将产品数量与对应的CategoriesBrands记录数相乘的解决方案）：

SQLFiddle：http://sqlfiddle.com/#!3/26d60/8

代码：

;with SelectedCategories as (
  select @IdCategory as IdCategory
  union all
  select c.IdCategory 
    from Categories c
    join SelectedCategories sc
      on sc.IdCategory = c.ParentCategoryId
)
select top 5
  b.IdBrand, 
  b.BrandName,
  count(p.IdProduct) AS 'ProductsCount'
from Brands b
join Products p
  on p.IdBrand = b.IdBrand
where b.IdBrand in (
  select cb.IdBrand
  from SelectedCategories c
  join CategoriesBrands cb
    on cb.IdCategory = c.IdCategory
 )
GROUP BY b.IdBrand, b.BrandName 
ORDER BY ProductsCount DESC

【讨论】：

非常感谢 wolf 的解决方案，这些正是我想要的。你节省了我很多时间。我只是对您的第二个解决方案显示诺基亚的 productcount 6 感到困惑，而产品表中只有 2 个诺基亚产品。这是为什么呢？
@Waqas 不错！这是因为这两种产品乘以诺基亚在类别品牌中的连接数。我会想办法解决这个问题并更新我的答案。
@Wolf，是的，现在它返回正确的产品计数。再次感谢您提供的所有帮助。