是否有可能用多個Inner Join重寫這個SQL查詢，以便執行速度更快？

Question

我有一張有200,000行的表格。我創建了一個視圖，根據不同的標準刪除此表中的數據片段，這些標準符合我對構成重複記錄的定義。我有下面這樣做的代碼，我想知道是否有人可以建議更快/更有效的編寫此查詢的方法。它目前需要大約20秒才能執行，但我最多希望幾秒鐘來執行此查詢（如果不少於這個）。我正在使用SQL Server 2005.我的SQL知識非常初學者，我很感激任何幫助。

WITH dsm_hardware_basic_cte AS 
(
SELECT TOP 100 PERCENT 
      dbo.dsm_hardware_basic.[UUID] 
      ,dbo.dsm_hardware_basic.[Name] 
      ,dbo.dsm_hardware_basic.[LastAgentExecution] 
      ,dbo.dsm_hardware_basic.[MaxUserRegistration] 
      ,REPLACE(RIGHT([MaxUserRegistration], CHARINDEX('/', REVERSE([MaxUserRegistration])) - 1),'_ADMIN','') AS [MaxUserUsername] 
      ,dbo.dsm_hardware_basic.[LastUserRegistration] 
      ,REPLACE(RIGHT([LastUserRegistration], CHARINDEX('/', REVERSE([LastUserRegistration])) - 1),'_ADMIN','') AS [LastUserUsername] 
      ,dbo.dsm_hardware_basic.[IPAddress] 
      ,dbo.dsm_hardware_basic.[HostName] 
      ,dbo.dsm_hardware_basic.[MACAddress] 
FROM  dbo.dsm_hardware_basic 
) 

SELECT  TOP 100 PERCENT 
      dsm_hardware_basic_cte.[UUID] 
      ,dsm_hardware_basic_cte.[Name] 
      ,dsm_hardware_basic_cte.[LastAgentExecution] 
      ,dsm_hardware_basic_cte.[MaxUserRegistration] 
      ,dsm_hardware_basic_cte.[LastUserRegistration] 
      ,dsm_hardware_basic_cte.[IPAddress] 
      ,dsm_hardware_basic_cte.[HostName] 
      ,dsm_hardware_basic_cte.[MACAddress] 
FROM  dsm_hardware_basic_cte 
      INNER JOIN 
      (
      SELECT [UUID] 
        ,ROW_NUMBER() OVER (PARTITION BY [Name], [MACAddress] ORDER BY [LastAgentExecution] DESC) AS [NameMACRowNum] 
      FROM  dsm_hardware_basic_cte 
      ) AS duplicate_NameMAC_filtered 
      ON duplicate_NameMAC_filtered.[UUID] = dsm_hardware_basic_cte.[UUID] 
      AND duplicate_NameMAC_filtered.[NameMACRowNum] = 1 
      INNER JOIN 
      (
      SELECT [UUID] 
        ,ROW_NUMBER() OVER (PARTITION BY [Name], [HostName] ORDER BY [LastAgentExecution] DESC) AS [NameHostNameRowNum] 
      FROM  dsm_hardware_basic_cte 
      ) AS duplicate_NameHostName_filtered 
      ON duplicate_NameHostName_filtered.[UUID] = dsm_hardware_basic_cte.[UUID] 
      AND duplicate_NameHostName_filtered.[NameHostNameRowNum] = 1 
      INNER JOIN 
      (
      SELECT [UUID] 
        ,ROW_NUMBER() OVER (PARTITION BY [HostName], [MACAddress] ORDER BY [LastAgentExecution] DESC) AS [HostNameMACRowNum] 
      FROM  dsm_hardware_basic_cte 
      ) AS duplicate_HostNameMAC_filtered 
      ON duplicate_HostNameMAC_filtered.[UUID] = dsm_hardware_basic_cte.[UUID] 
      AND duplicate_HostNameMAC_filtered.[HostNameMACRowNum] = 1 
      INNER JOIN 
      (
      SELECT [UUID] 
        ,ROW_NUMBER() OVER (PARTITION BY [HostName], [IPAddress] ORDER BY [LastAgentExecution] DESC) AS [HostNameIPAddressRowNum] 
      FROM  dsm_hardware_basic_cte 
      ) AS duplicate_HostNameIPAddress_filtered 
      ON duplicate_HostNameIPAddress_filtered.[UUID] = dsm_hardware_basic_cte.[UUID] 
      AND duplicate_HostNameIPAddress_filtered.[HostNameIPAddressRowNum] = 1 
      INNER JOIN 
      (
      SELECT [UUID] 
        ,ROW_NUMBER() OVER (PARTITION BY [Name], [MaxUserUsername] ORDER BY [LastAgentExecution] DESC) AS [NameMaxUserRowNum] 
      FROM  dsm_hardware_basic_cte 
      ) AS duplicate_NameMaxUser_filtered 
      ON duplicate_NameMaxUser_filtered.[UUID] = dsm_hardware_basic_cte.[UUID] 
      AND duplicate_NameMaxUser_filtered.[NameMaxUserRowNum] = 1 
      INNER JOIN 
      (
      SELECT [UUID] 
        ,ROW_NUMBER() OVER (PARTITION BY [Name], [LastUserUsername] ORDER BY [LastAgentExecution] DESC) AS [NameLastUserRowNum] 
      FROM  dsm_hardware_basic_cte 
      ) AS duplicate_NameLastUser_filtered 
      ON duplicate_NameLastUser_filtered.[UUID] = dsm_hardware_basic_cte.[UUID] 
      AND duplicate_NameLastUser_filtered.[NameLastUserRowNum] = 1 

Answer 1

我不知道你的需求是什麼，但我會嘗試重新編寫查詢這樣：

WITH dsm_hardware_basic_cte AS (
SELECT 
    d.[UUID] 
    ,d.[Name] 
    ,d.[LastAgentExecution] 
    ,d.[MaxUserRegistration] 
    ,REPLACE(RIGHT([MaxUserRegistration], CHARINDEX('/', REVERSE([MaxUserRegistration])) - 1),'_ADMIN','') AS [MaxUserUsername] 
    ,d.[LastUserRegistration] 
    ,REPLACE(RIGHT([LastUserRegistration], CHARINDEX('/', REVERSE([LastUserRegistration])) - 1),'_ADMIN','') AS [LastUserUsername] 
    ,d.[IPAddress] 
    ,d.[HostName] 
    ,d.[MACAddress] 
    ,ROW_NUMBER() OVER (PARTITION BY [Name], [MACAddress] ORDER BY [LastAgentExecution] DESC) AS [NameMACRowNum] 
    ,ROW_NUMBER() OVER (PARTITION BY [Name], [HostName] ORDER BY [LastAgentExecution] DESC) AS [NameHostNameRowNum] 
    ,ROW_NUMBER() OVER (PARTITION BY [HostName], [MACAddress] ORDER BY [LastAgentExecution] DESC) AS [HostNameMACRowNum] 
    ,ROW_NUMBER() OVER (PARTITION BY [HostName], [IPAddress] ORDER BY [LastAgentExecution] DESC) AS [HostNameIPAddressRowNum] 
    ,ROW_NUMBER() OVER (PARTITION BY [Name], [MaxUserUsername] ORDER BY [LastAgentExecution] DESC) AS [NameMaxUserRowNum] 
    ,ROW_NUMBER() OVER (PARTITION BY [Name], [LastUserUsername] ORDER BY [LastAgentExecution] DESC) AS [NameLastUserRowNum] 
FROM  dbo.dsm_hardware_basic as d 
) 

SELECT 
    c.[UUID] 
    ,c.[Name] 
    ,c.[LastAgentExecution] 
    ,c.[MaxUserRegistration] 
    ,c.[LastUserRegistration] 
    ,c.[IPAddress] 
    ,c.[HostName] 
    ,c.[MACAddress] 
FROM  dsm_hardware_basic_cte as c 
WHERE 
    c.[NameMACRowNum] = 1 
    or c.[NameHostNameRowNum] = 1 
    or c.[HostNameMACRowNum] = 1 
    or [HostNameIPAddressRowNum] = 1 
    or [NameMaxUserRowNum] = 1 
    or [NameLastUserRowNum] = 1 

我認爲您的查詢，我的是邏輯上等同。優化器可能足夠聰明，可以將您的查詢減少到我的查詢，但可以旋轉並查看！有兩點要注意：

1. 我用表的別名，以使其更有點可讀的（在我看來）
2. 我從你選擇刪除「頂百分之百」的條款。這不是必需的;這通常是人們採取的一種黑客行爲，以便他們可以通過視圖來完成「有序視圖」。不要這樣做。 :)

Answer 2

根據您的查詢計劃按LastAgentExecution排序需要19％的時間。首先在此列上創建一個索引。但是，如果我是你，我會改變使用「ROW_NUMBER（）OVER（PARTITION BY [Name]，[MACAddress] ORDER BY [LastAgentExecution] DESC）」類型的語法的習慣，因爲它似乎並不適用是非常有效的

Answer 3

取而代之的內部連接，嘗試用「存在」替換它們子句這樣

WHERE  EXISTS   
      ((SELECT [UUID],[NameMACRowNum] 
       FROM 
         (SELECT [UUID] 
           ,ROW_NUMBER() OVER (PARTITION BY [Name], [MACAddress] ORDER BY [LastAgentExecution] DESC) AS [NameMACRowNum] 
         FROM  dsm_hardware_basic_cte) AS duplicate_NameMAC_filtered 
      WHERE duplicate_NameMAC_filtered.[UUID] = dsm_hardware_basic_cte.[UUID] 
      AND duplicate_NameMAC_filtered.[NameMACRowNum] = 1) 

不知道它應該是存在與否存在，但它會是簡單，一旦剩下的改變工作中。