Question

我有三个表，其中两个是主表，另一个是map。它们在下面给出。

tbl_Category，具有列Id（PK）和名称

/ *

ID      NAME
1   Agriculture & Furtilizers
2   Apparel & Garments
3   Arts & Crafts   
4   Automobiles

* /

tbl_SubCategory

/*
Id      SubCategoryName                       CategoryId (FK, PK of above)
2   Badges, Emblems, Ribbons & Allied           2
3   Barcodes, Stickers & Labels                 2
4   Child Care & Nursery Products               2
9   Fabrics & Textiles                      2



*/

现在第三个表是tbl_Company_Category_Map，其中我持有公司的所有类别及其子类别。下面是它的架构和数据。

/*

CompanyCategoryId   SubCategoryId   CategoryId  CompanyId
10                   36             11          1
11                   38             11          1
12                   40             11          1


*/

上面，第一列是tbl_Company_Category_Map的PK，第二列是tbl_SubCategory的PK，第三列是tbl_Category的PK，最后一列是公司ID。现在我想要的是显示一个类别的每个子类别中列出的显示总公司。有点像这样。

Subcategory Name                                        Total COmpanies 
Apparel, Clothing & Garments                             1153
Badges, Emblems, Ribbons & Allied Products               4100
Barcodes, Stickers & Labels                              998
Child Care & Nursery Products                            2605
Cotton Bags, Canvas Bags, Jute Bags & Other Fabric Bags 2147

我正在使用查询：

BEGIN


SELECT     tbl_SubCategory.Name AS SubCategoryName, tbl_Category.Name AS CategoryName, TotalCompanies=(Select COUNT(*) From tbl_Company_Category_Map WHERE CategoryId = @Id)
FROM         tbl_Category INNER JOIN
                      tbl_Company_Category_Map ON tbl_Category.Id = tbl_Company_Category_Map.CategoryId INNER JOIN
                      tbl_SubCategory ON tbl_Company_Category_Map.SubCategoryId = tbl_SubCategory.Id
WHERE     (tbl_Company_Category_Map.CategoryId = @Id)
Group By tbl_SubCategory.Name , tbl_Company_Category_Map.CategoryId, tbl_Category.Name 
ORDER BY tbl_Company_Category_Map.CategoryId

END

我的问题是我每行的公司总数相同。请帮帮我。

Answer 1

尝试更改此内容：

TotalCompanies=(Select COUNT(*) From tbl_Company_Category_Map WHERE CategoryId = @Id)

......对此...

TotalCompanies=COUNT(*)

您已经按照（我认为是）正确的字段进行分组，您的WHERE子句会为您应用CategoryID过滤器。

Answer 2

我觉得你过分复杂了......请试一试：

select sc.Name, count(*) as company_count
from tbl_Category c
join tbl_SubCategory sc on c.ID = sc.CategoryID
join tbl_Company_Category_Map map on sc.ID = map.SubCategoryID
where c.ID = @ID
group by sc.Name

Answer 3

试试这个：

BEGIN


SELECT     tbl_SubCategory.Name AS SubCategoryName, COUNT(*) AS TotalCompanies
FROM       tbl_Category INNER JOIN
                      tbl_Company_Category_Map ON tbl_Category.Id = tbl_Company_Category_Map.CategoryId INNER JOIN
                      tbl_SubCategory ON tbl_Company_Category_Map.SubCategoryId = tbl_SubCategory.Id
WHERE     (tbl_Company_Category_Map.CategoryId = @Id)
Group By tbl_SubCategory.Name
ORDER BY tbl_SubCategory.Name

END

从sql表中获取计数

3 个答案: