復雜的SQL Join幫助！

Question

（有關快速回顧，請參見標題為DATA的部分。只能在圖A和圖B中獲得結果，我想要的是所需的結果，請嘗試在答案部分中發布的所有內容。）

總而言之，我一直在努力從我的應用程序中聰明地開始使用聯接。 男孩花了我一段時間，但我想我已經掌握了這個主意，但是我無法使該查詢正常工作。

請幫我！ 這是按原樣的聯接：

SELECT     TOP (100) PERCENT a.Id, a.DateCreated, a.DateModified, a.LastUpdatedBy, a.AccomplishmentTypeId, a.Title, a.Description, a.ApplicableDate, 
                  a.LocalId, at.Name AS AccomplishmentTypeName, a.Name AS AreaName, u.FirstName, u.LastName, ug.Name AS UserGroupName, 
                  ugo.Name AS OtherUserGroupName
FROM         dbo.Accomplishment AS a INNER JOIN
                  dbo.AccomplishmentType AS at ON at.Id = a.AccomplishmentTypeId INNER JOIN
                  dbo.AccomplishmentArea AS aal ON aal.AccomplishmentId = a.Id INNER JOIN
                  dbo.Area AS al ON al.Id = aal.AreaId INNER JOIN
                  dbo.UserAccomplishment AS ua ON ua.AccomplishmentId = a.Id INNER JOIN
                  dbo.[User] AS u ON u.Id = ua.UserId INNER JOIN
                  dbo.UserUserGroup AS uug ON uug.UserId = u.Id INNER JOIN
                  dbo.UserGroup AS ug ON ug.Id = uug.UserGroupId INNER JOIN
                  dbo.UserGroupType AS ugt ON ugt.Id = ug.UserGroupTypeId INNER JOIN
                  dbo.UserUserGroup AS uugo ON uugo.UserId = u.Id LEFT OUTER JOIN
                  dbo.UserGroup AS ugo ON ugo.Id = uugo.UserGroupId LEFT OUTER JOIN
                  dbo.UserGroupType AS ugto ON ugto.Id = ugo.UserGroupTypeId
WHERE     (ug.LocalId = 2) AND (ugo.LocalId <> 2) AND (ugto.LocalId = 4)
ORDER BY a.DateCreated DESC, u.LastName, u.FirstName, u.Id, UserGroupName

現在，這有點復雜，但是我正在做的是從所有相關表中選擇一項有成就的信息，其中有一個與之相關聯的用戶，而該用戶的用戶組的localId = 2，但是如果確實有，我還想返回該用戶所在的所有用戶組，其中usertype.localid = 4。

讓我給出一些示例數據來希望使這一點變得清楚，現在我在數據庫中有3個如下所示的成就：

- - - -（數據）

Accomplishment 1:
   User: John
      Usergroups: Group A (Of UserGroupType 2), Group B (Of UserGroupType 3), 
                  Group C (Of UserGroupType 4), Group D (Of UsergroupType 4)
Accomplishment 2:
   User: John
      Usergroups: Group A (Of UserGroupType 2), Group B (Of UserGroupType 3), 
                  Group C (Of UserGroupType 4), Group D (Of UsergroupType 4)
Accomplishment 3:
   User: Sue
      Usergroups: Group A (Of UserGroupType 2)

現在我上面的Join結果4行：

-------（圖A）：

 Accomplishment 1, John, Group A, Group C
 Accomplishment 1, John, Group A, Group D
 Accomplishment 2, John, Group A, Group C
 Accomplishment 2, John, Group A, Group D

現在，這是正確的，因為該用戶擁有的每個userGroup都有一行，其usergrouptype.localid為4，但是，如何使其顯示完成3？ 我首先將所有聯接作為內部聯接開始，然后認為進行最后的幾個左聯接將使它返回用戶，即使它沒有用戶組類型為localid 4的用戶組，也沒有。 基本上，我希望它返回組A中用戶的任何成就，並且如果他們具有usergrouptype 4的任何用戶組，則也返回所有這些用戶組。

有什么想法嗎？ 如果我不清楚，請告訴我，這太復雜了，我可能還沒有足夠的解釋。

編輯：

（有關快速回顧，請參見標題為DATA的部分。只能在圖A和圖B中獲得結果，我想要的是所需的結果，請嘗試在答案部分中發布的所有內容。）

HLGEM和Tom Hs的結果都相同，雖然更接近我的需求，但仍然相差甚遠。 現在，在圖B中我得到9個結果。

-------（圖B）：

Accomplishment 1, John, Group A, Group C
Accomplishment 1, John, Group A, Group D
Accomplishment 1, John, Group A, Null
Accomplishment 1, John, Group A, Group B (Group B is UsergroupType 3)
Accomplishment 3, Sue, Group A, Null
Accomplishment 2, John, Group A, Group C
Accomplishment 2, John, Group A, Group D
Accomplishment 2, John, Group A, Null
Accomplishment 2, John, Group A, Group B (Group B is UsergroupType 3)

因此，出於某種原因，即使John的用戶組的用戶組類型為4，該行也包含空行，並且其中包含組B的行的用戶組類型為3，因此不應顯示該行。

再次編輯：

（有關快速回顧，請參見標題為DATA的部分。只能在圖A和圖B中獲得結果，我想要的是所需的結果，請嘗試在答案部分中發布的所有內容。）

是的，我確實為此感到困惑，我已經嘗試了將東西放在where子句中的幾乎每一種組合，它要么是4行沒有成就3，要么是9行，其中用戶John每個成就又獲得了2行，或者6行沒有完成3和usergrouptype 3用戶組的額外行。 更令人困惑的是，在最后一行添加ugto.localid = 4似乎對結果沒有任何影響。 它向我顯示了一個用戶組，該用戶組的用戶組類型為3，在查詢的任何地方都看不到。

編輯5/02/10

（有關快速回顧，請參見標題為DATA的部分。只能在圖A和圖B中獲得結果，我想要的是所需的結果，請嘗試在答案部分中發布的所有內容。）

我認為我希望它的設置是不可能的嗎？ 無論如何，我想要的結果是這5行：

-------（所需結果）：

Accomplishment 1, John, Group A, Group C
Accomplishment 1, John, Group A, Group D
Accomplishment 2, John, Group A, Group C
Accomplishment 2, John, Group A, Group D
Accomplishment 3, Sue, Group A, Null

這是我嘗試過的所有內容及其提供的結果的列表：（請原諒糟糕的SSMS格式）

以下所有內容均基於此基本查詢：

開始查詢/嘗試1：

SELECT     TOP (100) PERCENT a.Id, a.DateCreated, a.DateModified, a.LastUpdatedBy, a.AccomplishmentTypeId, a.Title, a.Description, a.ApplicableDate, 
                  a.LocalId, at.Name AS AccomplishmentTypeName, al.Name AS AreaName, u.FirstName, u.LastName, ug.Name AS UserGroupName, 
                  ugo.Name AS OtherUsergroupName
  FROM         dbo.Accomplishment AS a INNER JOIN
                  dbo.AccomplishmentType AS at ON at.Id = a.AccomplishmentTypeId INNER    JOIN
                  dbo.AccomplishmentArea AS aal ON aal.AccomplishmentId = a.Id INNER JOIN
                  dbo.Area AS al ON al.Id = aal.AreaId INNER JOIN
                  dbo.UserAccomplishment AS ua ON ua.AccomplishmentId = a.Id INNER JOIN
                  dbo.[User] AS u ON u.Id = ua.UserId INNER JOIN
                  dbo.UserUserGroup AS uug ON uug.UserId = u.Id INNER JOIN
                  dbo.UserGroup AS ug ON ug.Id = uug.UserGroupId INNER JOIN
                  dbo.UserGroupType AS ugt ON ugt.Id = ug.UserGroupTypeId INNER JOIN
                  dbo.UserUserGroup AS uugo ON uugo.UserId = u.Id LEFT OUTER JOIN
                  dbo.UserGroup AS ugo ON ugo.Id = uugo.UserGroupId AND ugo.LocalId <> 2 LEFT OUTER JOIN
                  dbo.UserGroupType AS ugto ON ugto.Id = ugo.UserGroupTypeId AND ugto.LocalId = 4
 WHERE     (ug.LocalId = 2)
 ORDER BY a.DateCreated DESC, u.LastName, u.FirstName, u.Id, UserGroupName

結果： 圖B （請參見上面的方法） 為什么不好：出現 John的Null並顯示類型3的用戶組。

嘗試2：

嘗試1，減去所有的內聯聯接篩選（仍然在最后兩個聯接上保持左聯接）和以下where語句：

WHERE (ug.LocalId = 2)
  AND (ugo.LocalId <> 2 OR ugo.LocalId is null)
  AND (ugto.LocalId = 4 OR ugto.LocalId is null) 

結果： 圖A （請參見上面的方法） 不好的原因：不包括成就3

嘗試3：

與嘗試1相同，但在此行下開始更改：

 dbo.[User] AS u ON u.Id = ua.UserId INNER JOIN

在該行下的更改：

                  dbo.UserUserGroup AS uug ON uug.UserId = u.Id INNER JOIN
                  dbo.UserGroup AS ug ON ug.Id = uug.UserGroupId AND ug.LocalId = 2 INNER JOIN
                  dbo.UserGroupType AS ugt ON ugt.Id = ug.UserGroupTypeId INNER JOIN
                  dbo.UserUserGroup AS uugo ON uugo.UserId = u.Id LEFT OUTER JOIN
                  dbo.UserGroup AS ugo ON ugo.Id = uugo.UserGroupId AND ugo.LocalId <> 2 LEFT OUTER JOIN
                  dbo.UserGroupType AS ugto ON ugto.Id = ugo.UserGroupTypeId
WHERE     (ugto.LocalId = 4)
ORDER BY a.DateCreated DESC, u.LastName, u.FirstName, u.Id, UserGroupName

（有關快速回顧，請參見標題為DATA的部分。只能在圖A和圖B中獲得結果，我想要的是所需的結果，請嘗試在答案部分中發布的所有內容。）

Answer 1

@ChaosPandion關於重新格式化的評論是一個好主意，但是也許您需要一些幫助來了解什么是好的格式。 好吧，對於每個人來說，它可能都不同:-)，但是如果我正在編寫查詢，我將其格式設置如下：

SELECT  TOP (100) PERCENT
          a.Id,
          a.DateCreated,
          a.DateModified,
          a.LastUpdatedBy,
          a.AccomplishmentTypeId,
          a.Title,
          a.Description,
          a.ApplicableDate,  
          a.LocalId,
          at.Name AS AccomplishmentTypeName,
          a.Name AS AreaName,
          u.FirstName,
          u.LastName,
          ug.Name AS UserGroupName,  
          ugo.Name AS OtherUserGroupName 
FROM dbo.Accomplishment AS a
INNER JOIN dbo.AccomplishmentType AS at
  ON at.Id = a.AccomplishmentTypeId
INNER JOIN dbo.AccomplishmentArea AS aal
  ON aal.AccomplishmentId = a.Id
INNER JOIN dbo.Area AS al
  ON al.Id = aal.AreaId
INNER JOIN dbo.UserAccomplishment AS ua
  ON ua.AccomplishmentId = a.Id
INNER JOIN dbo.[User] AS u
  ON u.Id = ua.UserId
INNER JOIN dbo.UserUserGroup AS uug
  ON uug.UserId = u.Id
INNER JOIN dbo.UserGroup AS ug
  ON ug.Id = uug.UserGroupId
INNER JOIN dbo.UserGroupType AS ugt
  ON ugt.Id = ug.UserGroupTypeId
INNER JOIN dbo.UserUserGroup AS uugo
  ON uugo.UserId = u.Id
LEFT OUTER JOIN dbo.UserGroup AS ugo
  ON ugo.Id = uugo.UserGroupId
LEFT OUTER JOIN dbo.UserGroupType AS ugto
  ON ugto.Id = ugo.UserGroupTypeId 
WHERE ug.LocalId = 2 AND
      ugo.LocalId <> 2 AND
      ugto.LocalId = 4
ORDER BY a.DateCreated DESC,
         u.LastName,
         u.FirstName,
         u.Id,
         UserGroupName

我認為這種格式使其更易於閱讀。

分享並享受。

Answer 2

我不確定我是否完全了解您要執行的操作，但是我認為您需要將標准移至“左外部聯接”中。 如果將其放在WHERE子句中，則如果LEFT OUTER JOIN未找到匹配項，則這些列將顯示為NULL，因此它們將無法通過WHERE子句檢查。 您實際上是在將“左外部連接”轉換為“內部連接”。

FROM
    dbo.Accomplishment AS a
INNER JOIN dbo.AccomplishmentType AS at ON
    at.Id = a.AccomplishmentTypeId
INNER JOIN dbo.AccomplishmentArea AS aal ON
    aal.AccomplishmentId = a.Id
INNER JOIN dbo.Area AS al ON
    al.Id = aal.AreaId
INNER JOIN dbo.UserAccomplishment AS ua ON
    ua.AccomplishmentId = a.Id
INNER JOIN dbo.[User] AS u ON
    u.Id = ua.UserId
INNER JOIN dbo.UserUserGroup AS uug ON
    uug.UserId = u.Id
INNER JOIN dbo.UserGroup AS ug ON
    ug.Id = uug.UserGroupId AND
    ug.localid = 2
INNER JOIN dbo.UserGroupType AS ugt ON
    ugt.Id = ug.UserGroupTypeId
INNER JOIN dbo.UserUserGroup AS uugo ON
    uugo.UserId = u.Id
LEFT OUTER JOIN dbo.UserGroup AS ugo ON
    ugo.Id = uugo.UserGroupId AND
    ugo.localid <> 2
LEFT OUTER JOIN dbo.UserGroupType AS ugto ON
    ugto.Id = ugo.UserGroupTypeId
WHERE
    ugto.localid = 4
ORDER BY
    a.DateCreated DESC, u.LastName, u.FirstName, u.Id, UserGroupName

Answer 3

在學習左聯接時，您犯了一個經典錯誤，您在where子句中放置了將其變為內部聯接的條件

嘗試這個

SELECT     a.Id, a.DateCreated, a.DateModified, a.LastUpdatedBy, a.AccomplishmentTypeId, a.Title,
a.Description, a.ApplicableDate,  a.LocalId, at.Name AS AccomplishmentTypeName, 
a.Name AS AreaName, u.FirstName, u.LastName, ug.Name AS UserGroupName, ugo.Name AS OtherUserGroupName 
FROM        dbo.Accomplishment AS a 
INNER JOIN  dbo.AccomplishmentType AS at ON at.Id = a.AccomplishmentTypeId 
INNER JOIN  dbo.AccomplishmentArea AS aal ON aal.AccomplishmentId = a.Id 
INNER JOIN  dbo.Area AS al ON al.Id = aal.AreaId 
INNER JOIN  dbo.UserAccomplishment AS ua ON ua.AccomplishmentId = a.Id 
INNER JOIN  dbo.[User] AS u ON u.Id = ua.UserId 
INNER JOIN  dbo.UserUserGroup AS uug ON uug.UserId = u.Id 
INNER JOIN  dbo.UserGroup AS ug ON ug.Id = uug.UserGroupId 
INNER JOIN  dbo.UserGroupType AS ugt ON ugt.Id = ug.UserGroupTypeId 
INNER JOIN  dbo.UserUserGroup AS uugo ON uugo.UserId = u.Id 
LEFT OUTER JOIN  dbo.UserGroup AS ugo ON ugo.Id = uugo.UserGroupId  AND ugo.LocalId <> 2
LEFT OUTER JOIN  dbo.UserGroupType AS ugto ON ugto.Id = ugo.UserGroupTypeId  AND ugto.LocalId = 4
WHERE     ug.LocalId = 2 
ORDER BY a.DateCreated DESC, u.LastName, u.FirstName, u.Id, UserGroupName 

請參閱此鏈接以獲取對此的解釋： http : //wiki.lessthandot.com/index.php/WHERE_conditions_on_a_LEFT_JOIN

Answer 4

到目前為止，這是我重寫的內容：

SELECT a.Id, a.DateCreated, a.DateModified, a.LastUpdatedBy, a.AccomplishmentTypeId, 
       a.Title, a.Description, a.ApplicableDate, a.LocalId, 
       at.Name AS AccomplishmentTypeName, a.Name AS AreaName, u.FirstName, 
       u.LastName, ug.Name AS UserGroupName, ugo.Name AS OtherUserGroupName
  FROM dbo.Accomplishment a 
  JOIN dbo.AccomplishmentType AS at ON at.Id = a.AccomplishmentTypeId 
  JOIN dbo.AccomplishmentArea AS aal ON aal.AccomplishmentId = a.Id 
  JOIN dbo.Area AS al ON al.Id = aal.AreaId 
  JOIN dbo.UserAccomplishment AS ua ON ua.AccomplishmentId = a.Id 
  JOIN dbo.[User] AS u ON u.Id = ua.UserId 
  JOIN dbo.UserUserGroup AS uug ON uug.UserId = u.Id 
  JOIN dbo.UserGroupType AS ugt ON ugt.Id = ug.UserGroupTypeId 
  JOIN dbo.UserGroup AS ug ON ug.Id = uug.UserGroupId 
  JOIN dbo.UserGroupType AS ugto ON ugto.Id = ug.UserGroupTypeId
 ORDER BY a.DateCreated DESC, u.LastName, u.FirstName, u.Id, UserGroupName

您有一個到UserUserGroup的多余UserUserGroup ，並且可以合並到UserGroup的聯接，因為LEFT JOIN條件將取消上一次聯接到同一表的操作。

Answer 5

您的聯接都很好。 這是過濾！

如果編寫的過濾器不允許左連接表中的空值，那么您的過濾器將刪除左連接允許的其他記錄。

ugo和ugto均可通過LEFT JOIN到達

WHERE (ug.LocalId = 2)
  AND (ugo.LocalId <> 2 OR ugo.LocalId is null)
  AND (ugto.LocalId = 4 OR ugto.LocalId is null) 

PS-混合JOIN和FILTERING標准（在ON或在WHERE中都使用）是導致精神錯亂的秘訣。 保持理智！

---

編輯：在連接中發現錯誤：

INNER JOIN dbo.UserUserGroup AS uugo ON uugo.UserId = u.Id

應該

LEFT JOIN dbo.UserUserGroup AS uugo ON uugo.UserId = u.Id