获取带有附加信息的重复项

Question

我已经继承了一个数据库，并且在构建正在运行的SQL查询时遇到了问题。

假设这是数据：

[Products] 

| Id | DisplayId  | Version | Company | Description | 
|---- |----------- |---------- |-----------| ----------- | 
| 1  | 12345   | 0   | 16  | Random  | 
| 2  | 12345   | 0   | 2   | Random 2  | 
| 3  | AB123   | 0   | 1   | Random 3  | 
| 4  | 12345   | 1   | 16  | Random 4  | 
| 5  | 12345   | 1   | 2   | Random 5  | 
| 6  | AB123   | 0   | 5   | Random 6  | 
| 7  | 12345   | 2   | 16  | Random 7  | 
| 8  | XX45   | 0   | 5   | Random 8  | 
| 9  | XX45   | 0   | 7   | Random 9  | 
| 10 | XX45   | 1   | 5   | Random 10  | 
| 11 | XX45   | 1   | 7   | Random 11  | 


[Companies] 

| Id | Code  | 
|---- |-----------| 
| 1  | 'ABC'  | 
| 2  | '456'  | 
| 5  | 'XYZ'  | 
| 7  | 'XYZ'  | 
| 16 | '456'  | 

的Version列是一个版本号。数字越大表示更新的版本。 Company列是Id列中引用Companies表的外键。 还有另一个表ProductData与ProductId列参考Products.Id。

现在我需要根据DisplayId和相应的Companies.Code找到重复项。应加入ProductData表以显示标题（ProductData.Title），并且只有最近的应该包含在结果中。因此，预期的结果是：

| Id | DisplayId  | Version | Company | Description | ProductData.Title | 
|---- |----------- |---------- |-----------|------------- |------------------ | 
| 5  | 12345   | 1   | 2   | Random 2  | Title 2   | 
| 7  | 12345   | 2   | 16  | Random 7  | Title 7   | 
| 10 | XX45   | 1   | 5   | Random 10  | Title 10   | 
| 11 | XX45   | 1   | 7   | Random 11  | Title 11   | 

• 因为XX45有2个“项”：一个公司5和一个与公司7，但两家公司共享相同的代码。
• 因为12345有2个“条目”：一个与公司2和一个与公司16，但两家公司共享相同的代码。请注意，两者的最新版本不同（公司16的条目的版本2和公司2的条目的版本1）
• 不应包含ABC123，因为它的2个条目具有不同的公司代码。

我很想知道您的见解...

Answer 1

试试这个：

SELECT b.ID,displayid,version,company,productdata.title 
FROM 
(select A.ID,a.displayid,version,a.company,rn,a.code, COUNT(displayid) over (partition by displayid,code) cnt from 
(select Prod.ID,displayid,version,company,Companies.code, Row_number() over (partition by displayid,company order by version desc) rn 
from Prod inner join Companies on Prod.Company = Companies.id) a 
where a.rn=1) b inner join productdata on b.id = productdata.id where cnt =2 

Answer 2

如果我理解正确的话，你可以使用CTE从您的表发现所有的重复的行，那么你可以只使用来自SELECT CTE甚至添加更多操作。

WITH CTE AS(
    SELECT Id,DisplayId,Version,Company,Description,ProductData.Title 
     RN = ROW_NUMBER()OVER(PARTITION BY DisplayId, Company ORDER BY p.Id DESC) 
    FROM dbo.YourTable1 
) 

SELECT * 
FROM CTE 

Answer 3

根据您的样本数据，你只需要JOIN表：

SELECT 
    p.Id, p.DisplayId, p.Version, p.Company, d.Title 
    FROM Products AS p 
    INNER JOIN Companies AS c ON p.Company = c.Id 
    INNER JOIN ProductData AS d ON d.ProductId = p.Id; 

但是如果你想要最新的一个，你可以使用ROW_NUMBER()：

WITH CTE 
AS 
(
    SELECT 
    p.Id, p.DisplayId, p.Version, p.Company, d.Title, 
    ROW_NUMBER() OVER(PARTITION BY p.DisplayId,p.Company ORDER BY p.Id DESC) AS RN 
    FROM Products AS p 
    INNER JOIN Companies AS c ON p.Company = c.Id 
    INNER JOIN ProductData AS d ON d.ProductId = p.Id 
) 
SELECT * 
FROM CTE 
WHERE RN = 1; 

sample fiddle

| Id | DisplayId | Version | Company | Title | 
|----|-----------|---------|---------|----------| 
| 5 |  12345 |  1 |  2 | Title 5 | 
| 7 |  12345 |  2 |  16 | Title 7 | 
| 10 |  XX45 |  1 |  5 | Title 10 | 
| 11 |  XX45 |  1 |  7 | Title 11 | 

Answer 4

您必须先获取当前版本，然后才能看到DisplayID +代码显示的次数。然后基于此，您只能选择计数大于1的计数。然后，您可以在最终查询上INNER JOIN ProductData以获取标题。

WITH 
MaxVersion AS --Get the current versions 
(
    SELECT 
     MAX(Version) AS Version, 
     DisplayID, 
     Company 
    FROM 
     #TmpProducts 
    GROUP BY 
     DisplayID, 
     Company 
) 
,CTE AS 
(
    SELECT 
     p.DisplayID, 
     c.Code, 
     COUNT(*) AS RowCounter 
    FROM 
     #TmpProducts p 
    INNER JOIN 
     #TmpCompanies c 
     ON 
      c.ID = p.Company 
    INNER JOIN 
     MaxVersion mv 
     ON 
      mv.DisplayID = p.DisplayID 
     AND mv.Version = p.Version 
     AND mv.Company = p.Company 
    GROUP BY 
     p.DisplayID, 
     c.Code 
) 

SELECT 
    p.* 
FROM 
    #TmpProducts p 
INNER JOIN 
    CTE c 
    ON 
     c.DisplayID = p.DisplayID 
INNER JOIN 
    MaxVersion mv 
    ON 
     mv.DisplayID = p.DisplayID 
    AND mv.Company = p.Company 
    AND mv.Version = p.Version 
WHERE 
    c.RowCounter > 1