复杂的SQL查询 – 查找匹配多个不同外键的项目

发布时间：2020-12-12 16:25:59 所属栏目：MsSql教程来源：网络整理

导读：因此,假设您有一个Products表(ID int,Name nvarchar(200))和另外两个表ProductsCategories(ProductID int,CategoryID int)和InvoiceProducts(InvoiceID int,ProductID int). 我需要编写一个查询来生成一组与一组给定的发票ID和类别ID匹配的产品,这样产品列表

因此,假设您有一个Products表(ID int,Name nvarchar(200))和另外两个表ProductsCategories(ProductID int,CategoryID int)和InvoiceProducts(InvoiceID int,ProductID int).

我需要编写一个查询来生成一组与一组给定的发票ID和类别ID匹配的产品,这样产品列表就可以匹配所有指定的类别和所有指定的发票,而不会回退到动态SQL.想象一下,我需要找到1类和2类以及发票3和4中的产品列表.

首先,我编写了一个存储过程,将类别ID和发票ID作为字符串接受,并将它们解析为表格：

CREATE PROCEDURE dbo.SearchProducts (@categories varchar(max),@invoices varchar(max))
 AS BEGIN
      with catids as (select cast([value] as int) from dbo.split(@categories,' ')),invoiceids as (select cast([value] as int) from dbo.split(@invoices,' '))
           select * from products --- insert awesomeness here
 END

我提出的不同解决方案看起来很糟糕,而且表现更差.我发现的最好的事情是生成一个由所有条件的左连接组成的视图,但这似乎非常昂贵,并没有解决匹配指定的所有不同键的问题.

更新：这是我编写的一个示例查询,可以产生预期的结果.我错过了任何优化机会吗？像忍者的魔法独角兽矩阵操作一样？

with catids as (select distinct cast([value] as int) [value] from dbo.split(@categories,invoiceids as (select distinct cast([value] as int) [value] from dbo.split(@invoices,' '))

  select pc.ProductID from ProductsCategories pc (nolock)
    inner join catids c on c.value = pc.CategoryID 
    group by pc.ProductID 
    having COUNT(*) = (select COUNT(*) from catids)  
  intersect
  select ip.ProductID from InvoiceProducts ip (nolock)
    inner join invoiceids i on i.value = ip.InvoiceID 
    group by ip.ProductID 
    having COUNT(*) = (select COUNT(*) from invoiceids)

解决方法

如果您在(ProductID,CategoryID)和(ProductID,InvoiceID)上都有唯一索引：

SELECT  ProductID
FROM    (
        SELECT  ProductID
        FROM    ProductInvoice
        WHERE   InvoiceID IN (1,2)
        UNION ALL
        SELECT  ProductID
        FROM    ProductCategory pc
        WHERE   CategoryID IN (3,4)
        ) q
GROUP BY
        ProductID
HAVING  COUNT(*) = 4

或者,如果您的值以CSV字符串传递：

WITH    catids(value) AS
        (
        SELECT  DISTINCT CAST([value] AS INT)
        FROM    dbo.split(@categories,' '))
        ),(
        SELECT  DISTINCT CAST([value] AS INT)
        FROM    dbo.split(@invoices,' '))
        )
SELECT  ProductID
FROM    (
        SELECT  ProductID
        FROM    ProductInvoice
        WHERE   InvoiceID IN
                (
                SELECT  value
                FROM    invoiceids
                )
        UNION ALL
        SELECT  ProductID
        FROM    ProductCategory pc
        WHERE   CategoryID IN
                (
                SELECT  value
                FROM    catids
                )
        ) q
GROUP BY
        ProductID
HAVING  COUNT(*) = 
        (
        SELECT  COUNT(*)
        FROM    catids
        ) + 
        (
        SELECT  COUNT(*)
        FROM    invoiceids
        )

请注意,在SQL Server 2008中,您可以将表值参数传递到存储过程中.

（编辑：李大同）

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