SQL Server 错误：最大前缀数。最大值为 3. 使用连接语法

Question

尝试运行跨服务器更新：

UPDATE ASILIVE.CustomerManagementSystem.dbo.Sessions
SET ASILIVE.CustomerManagementSystem.dbo.Sessions.VarianceAmount=Variances.VarianceAmount
FROM ASILIVE.CustomerManagementSystem.dbo.Sessions
    INNER JOIN Variances
    ON ASILIVE.CustomerManagementSystem.dbo.Sessions.SessionGUID = Variances.SessionGUID
WHERE ASILIVE.CustomerManagementSystem.dbo.Sessions.VarianceAmount <> Variances.VarianceAmount

给出错误：

Msg 117, Level 15, State 2, Line 5
The number name 'ASILIVE.CustomerManagementSystem.dbo.Sessions' contains 
more than the maximum number of prefixes. The maximum is 3.

什么给了？

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另见

• SQL Server Error: "maximum number of prefixes. The maximum is 3" with subselect syntax
  （处理子选择语法；这个问题处理连接语法）

---

不重要的研究：

我尝试将事物随机别名为s：

UPDATE ASILIVE.CustomerManagementSystem.dbo.Sessions s
SET s.VarianceAmount=Variances.VarianceAmount
FROM ASILIVE.CustomerManagementSystem.dbo.Sessions s
    INNER JOIN Variances
    ON s.SessionGUID = Variances.SessionGUID
WHERE s.VarianceAmount <> Variances.VarianceAmount

但这不起作用：

Msg 117, Level 15, State 2, Line 5
The number name 'ASILIVE.CustomerManagementSystem.dbo.Sessions' contains 
more than the maximum number of prefixes. The maximum is 3.

Hamlin 建议添加括号：

UPDATE [ASILIVE].[CustomerManagementSystem].dbo.Sessions
SET [ASILIVE].[CustomerManagementSystem].dbo.Sessions.DisciplineVarianceAmount=DisciplineVariances.VarianceAmount
FROM [ASILIVE].[CustomerManagementSystem].dbo.Sessions
    INNER JOIN DisciplineVariances
    ON [ASILIVE].[CustomerManagementSystem].dbo.Sessions.SessionGUID = DisciplineVariances.SessionGUID
WHERE [ASILIVE].[CustomerManagementSystem].dbo.Sessions.DisciplineVarianceAmount <> DisciplineVariances.VarianceAmount

但这不起作用：

Msg 117, Level 15, State 2, Line 5
The number name 'ASILIVE.CustomerManagementSystem.dbo.Sessions' contains
more than the maximum number of prefixes. The maximum is 3.

Answer 1

通常，您至少需要在链接服务器名称周围添加括号。

[ASILIVE].[CustomerManagementSystem].dbo.Sessions

编辑 - 另外试试这个

UPDATE S
SET DisciplineVarianceAmount = Variances.VarianceAmount
FROM [ASILIVE].[CustomerManagementSystem].dbo.Sessions as S
    INNER JOIN Variances ON S.SessionGUID = Variances.SessionGUID
WHERE S.VarianceAmount <> Variances.VarianceAmount

Answer 2

你真的很喜欢打字吗？ :-)

UPDATE s
  SET s.DisciplineVarianceAmount = v.VarianceAmount
  FROM [ASILIVE].[CustomerManagementSystem].dbo.Sessions AS s
  INNER JOIN dbo.Variances AS v
  ON s.SessionGUID = v.SessionGUID
  AND s.VarianceAmount <> v.VarianceAmount;

请注意，如果任一差异金额当前为 NULL，您可能需要在此处描述要执行的操作。