Question

我正在构建asp.net mvc app，我在多个表上编写SQL存储过程时遇到了麻烦。

我有7个不同的表，彼此相互连接。

Customer
    Id
    Name

CustomerBook
    Id
    CustomerId
    BookId

Book
    Id
    Name

BookType
    Id
    BookId
    TypeId

Type
    Id
    Name

BookCategory
    BookId
    CategoryId

Category
    Id
    Name

它看起来像那样。

CustomerBook.CustomerId = Customer.Id 
CustomerBook.BookId = Book.Id
BookCategory.BookId = Book.Id
BookCategory.CategoryId = Category.Id
BookType.BookId = Book.Id
BookType.TypeId = Book.Id

如果我没弄错的话。

我现在要做的是编写存储过程，以获取并显示特定用户“购买”的所有书籍。

我想展示：

Book name
Book type
Book category

...为当前登录会话的每个用户。

后来我想把数据输入控制器......但这是另一天的问题。

由于我对程序很新，只知道一点SQL，我真的很感谢你的帮助！

这是我到目前为止所尝试的：

CREATE PROCEDURE [dbo].[getBookByCustomerId]
@Id int
AS
BEGIN
    SET NOCOUNT ON;
    SELECT * FROM [Customer] WHERE Id = @id
END

现在我卡住了......

Answer 1

这样的事情应该这样做：

CREATE PROCEDURE [dbo].[getBookByCustomerId]
    @Id INT
AS
     BEGIN
         SET NOCOUNT ON;
         SELECT
             B.Id,
             B.Name,
             T.Name,
             C.Name
         FROM Book B
         INNER JOIN CustomerBook CB ON B.Id = CB.BookId
         INNER JOIN BookType BT ON B.ID = BT.BookID
         INNER JOIN Type T ON BT.TypeID = T.ID
         INNER JOIN BookCategory BC ON B.BookId = BC.BookId
         INNER JOIN Category C ON BC.CategoryId = C.CategoryId
         WHERE CB.CustomerID = @Id;
     END;

它将获取BookID和Name，其中customerID等于传入的值。

INNER JOIN只会获取两个表中的记录，here是了解联接的好帖子。

Answer 2

此参数@Id代表客户ID。

CREATE PROCEDURE [dbo].[getBookByCustomerId]
@Id int
AS
BEGIN
    SET NOCOUNT ON;
    SELECT 
    B.Id, B.Name, T.Name, C.Name 
    FROM 
    Customer C
    INNER JOIN 
    CustomerBook CB ON C.Id = CB.CustomerId
    INNER JOIN
    Book B ON B.Id = CB.Id
    INNER JOIN
    BookType BT ON B.Id = BT.BookId
    INNER JOIN 
    Type T ON BT.TypeId = T.Id
    INNERJOIN
    BookCategory BC ON
    BC.BookId = B.BookId
    INNER JOIN
    Category CT on CT.Id = BC.CategoryId

    WHERE 
    C.Id = @Id  

END

多个表上的SQL存储过程

2 个答案: