使用别名表更新 SQL 仍然返回“表不明确"；错误 [英] Update SQL with Aliased tables still returns "table is ambiguous" error

问题描述

我正在尝试运行以下更新，但遇到表不明确"错误.

I am trying to run the below update but running into the "table is ambiguous" error.

UPDATE dbo.cg
SET cg.column = gId.ID
FROM    dbo.a
        INNER JOIN dbo.cg as cId ON cId.[a] = dbo.a.[c]
        INNER JOIN dbo.cg as gId ON gId.[a] = dbo.a.[b];

表 dbo.a 包含用于更新 cg 中的值的数据，这些数据基于与同一表相对于不同列中的值的关系.这是一个自引用层次结构.

The table dbo.a contains data to update a value in cg based on a relationship to same table against a value in a different column. It is a self-referencing hierarchy.

正如你所看到的，一切都是别名，所以我有点困惑为什么这不会运行.

As you can see, everything is aliased so I am a bit confused why this won't run.

非常感谢您提供的任何帮助.

Many thanks in advance for any help that can be provided.

推荐答案

在 SQL Server 中，您应该在 update 而不是表中使用 alias.此外，您没有名为 cg 的别名.所以是这样的:

In SQL Server, you should use the alias in the update, not the table. In addition, you have no alias called cg. So something like this:

UPDATE cId
SET column = gId.ID
FROM dbo.a a INNER JOIN
     dbo.cg cId
     ON cId.[a] = a.[c] INNER JOIN
     dbo.cg gId
     ON gId.[a] = a.[b];

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