T-SQL 高级连接答案

【问题标题】：T-SQL Advanced JoinT-SQL 高级连接
【发布时间】：2022-11-17 00:51:46
【问题描述】：

我正在努力实现以下结果；

Customer	Purchase Total ($)
Customer A	1234.56
Customer B	5678.90
Customer C
Customer D
Customer E	91011.23

表结构如下；

Table Name	Fields
Invoice	InvoiceId, InvoiceType, CustomerId, DateIssued
Invoice Lines	LineId, InvoiceId, ProductId, Date, Price, Quantity, LineTotal
Product	ProductId, Code, name
Customer	CustomerId, Status, Region, Code, Name

我必须使用以下过滤器得出结果；

Filter	Value
Product.Code	GTN
Invoice.InvoiceType	All invoices (Returns and Sales) are stored in the same table hence, in order to obtain correct result, I need to subtract returns from sales) Sales Invoice Type is 8 and Returns Invoice Type is 3
Customer.Status	0
Customer.Region	London
Customer.Code	Starts with M
Invoice.Date	Year: 2022 Month: 10

我尝试了什么：我尝试了很多其他的东西，下面是我最新的代码，但我得到了错误的结果。

SELECT C.Name, 
    (SELECT SUM(IL.LineTotal) 
    FROM Invoice I 
    INNER JOIN InvoiceLine IL ON I.InvoiceId= IL.InvoiceId 
    INNER JOIN Product P ON IL.ProductId = P.ProductId
    WHERE IL.CustomerId = C.CustomerId AND P.CODE LIKE 'GTN.%' AND I.TRCODE = 8 AND YEAR(IL.Date) = 2022 AND MONTH(IL.Date) = 10 AND C.Code LIKE 'M.%' AND C.Region = 'London') -
    (SELECT SUM(LI.LineTotal) 
    FROM Invoice I 
    INNER JOIN InvoiceLine IL ON I.InvoiceId= IL.InvoiceId 
    INNER JOIN Product P ON IL.ProductId = P.ProductId
    WHERE IL.CustomerId = C.CustomerId AND P.CODE LIKE 'WLT.%' AND I.TRCODE = 3 AND YEAR(IL.Date) = 2022 AND MONTH(IL.Date) = 10 AND C.Code LIKE 'M.%' AND C.Region = 'London') AS TOTAL
FROM Invoice I
LEFT JOIN Customer C ON I.CustomerId = C.CustomerId
WHERE C.Code LIKE 'M.%'
GROUP BY C.CustomerId, C.Code, C.Name
ORDER BY C.Name;

因为要求只将代码以特定字母开头的产品的总计带到结果中，所以我不能在 Invoice 表上工作，而是在 InvoiceLines 表上工作。也因为还需要列出那些没有购买任何东西的客户，所以我想对 Customer 表使用 LEFT JOIN。

任何帮助，将不胜感激。

【问题讨论】：

意味深长示例数据和预期结果（最好是 DDL 和 DML 语句）将真正帮助我们帮助您。您的查询看起来根本不正确；特别是当你有 3 个 Invoice 的实例时，它们都别名为 I，并且一些范围是共享的。你也有一个 GROUP BY 但实际上并没有聚合任何该范围内的列，那么为什么要有 GROUP BY 呢？
另外，当您需要列 Code 时，为什么将 LEFT JOIN 更改为 Customer必须有一个非NULL 值？如果没有找到行，Code 的值不可能是非NULL。
我正在尝试检索数据以分析每个客户特定商品的月销售额。部分分析还需要列出该月未进行任何购买的客户，因此我认为我可以通过 LEFT JOIN 实现这一点。我对 SQL 的了解非常有限，所以如果它没有任何意义，我深表歉意。所有 GROUP BY 语句都在那里，因为 SSMS 抱怨没有它们。
SUM(LI.LineTotal) 甚至不起作用，您的查询中没有别名为 LI 的对象。
抱歉，应该是 IL。我已经更正了

标签： sql sql-server tsql

【解决方案1】：

我为你做了腿部工作。这是 SQL 小提琴。您必须针对所有特定变量和过滤器对其进行调整。在需要的地方添加其他限制器应该很容易。

SQL Fiddle

MS SQL Server 2017 架构设置:

CREATE TABLE Invoice (
  InvoiceId int not null
  , InvoiceType nvarchar(50) null
  , CustomerId int not null
  , DateIssued datetime not null
);

CREATE TABLE InvoiceLine (
  LineId int IDENTITY(1,1) not null
  , InvoiceId int not null
  , ProductId int not null
  , [Date] datetime null
  , Quantity decimal(19,4) not null
  , LineTotal decimal(19,2) not null
);

CREATE TABLE Product (
  ProductId int IDENTITY(1,1) not null
  , [Code] nvarchar(256) not null
  , Name nvarchar(50) not null
);

CREATE TABLE Customer (
  CustomerId int IDENTITY(1,1) not null
  , [Status] nvarchar(50) null
  , Region nvarchar(50) null
  , [Code] nvarchar(50) null
  , Name nvarchar(50) not null
);

INSERT INTO Customer ([Status], Name, [Code], Region)
VALUES ('Active', 'ABC Co.', 'Mega', 'London')
  , ('Active', 'XYZ Co.', 'Mega', 'London')
  , ('Active', 'TTL Co.', 'Mega', 'London')
;

INSERT INTO Product ([Code], Name) 
VALUES ('A1B2C3','Widget A')
  , ('D4E5F6', 'Widget D')
  , ('G7H8I9', 'Widget G')
;

INSERT INTO Invoice (InvoiceId, InvoiceType, CustomerId, DateIssued)
VALUES (1234111, 'Invoice', 1, '2022-10-16 00:00:00')
  , (1234777, 'Invoice', 2, '2022-10-14 00:00:00')
  , (1234888, 'Return', 1, '2022-10-16 00:00:00')
;

INSERT INTO InvoiceLine (InvoiceId, ProductId, Quantity, LineTotal)
VALUES (1234111, 1, 1.0000, 56.98)
  , (1234111, 2, 2.0000, 48.28)
  , (1234777, 2, 5.0000, 120.07)
  , (1234777, 3, 2.5000, 99.84)
  , (1234888, 1, 1.0000, 56.98)
;

查询 1:

DECLARE @GTN nvarchar(50) = 'A1'
DECLARE @WLT nvarchar(50) = 'D4'

SELECT
  c.Name
  , ISNULL((
      SELECT SUM(il.LineTotal) as LineTotal
      FROM Invoice as i
        INNER JOIN InvoiceLine as il
          ON il.InvoiceId = i.InvoiceId
        INNER JOIN Product as p
          ON p.ProductId = il.ProductId
          AND p.[Code] like @GTN + '%'
      WHERE i.CustomerId = c.CustomerId
        AND i.DateIssued >= DateFromParts(2022, 10, 1)
        AND i.DateIssued < DateFromParts(2022, 11, 1)
    ),0) --WidgetATotalSales
  - ISNULL((
      SELECT SUM(il.LineTotal) as LineTotal
      FROM Invoice as i
        INNER JOIN InvoiceLine as il
          ON il.InvoiceId = i.InvoiceId
        INNER JOIN Product as p
          ON p.ProductId = il.ProductId
          AND p.[Code] like @WLT + '%'
      WHERE i.CustomerId = c.CustomerId
        AND i.DateIssued >= DateFromParts(2022, 10, 1)
        AND i.DateIssued < DateFromParts(2022, 11, 1)
    ),0) --WidgetDTotalSales
    as Total
FROM Customer as c
WHERE 1=1
  AND c.[Code] like 'M%'
  AND c.[Status] = 'Active'
  AND c.[Region] = 'London'

Results:

|    Name |   Total |
|---------|---------|
| ABC Co. |   65.68 |
| XYZ Co. | -120.07 |
| TTL Co. |       0 |

【讨论】：