更新另一个表时必须声明标量变量@tablename [duplicate]

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这个问题在这里已有答案：

How to fix “Must declare the scalar variable” error when referencing table variable? 1 answer
如何在引用表变量时修复“必须声明标量变量”错误？ 1个答案

I am trying to do:

我想做：

update existingTable
set code = @declaredTable.code
where id = @declaredTable.id

but when I do this I get the error:

但是当我这样做时，我得到错误：

Must declare the scalar variable "@declaredTable"

必须声明标量变量“@declaredTable”

twice.

两次。

How do I update values of an existing tables to values from a declared tables?

如何将现有表的值更新为声明表中的值？

Why doesn't this work?

为什么这不起作用？

Any help would be much appreciated!

任何帮助将非常感激！

1 个解决方案

You need JOIN :

你需要加入：

UPDATE e 
      SET e.code = d.code
FROM existingTable e INNER JOIN 
     @declaredTable d
     on d.id = e.id;

You need JOIN :

你需要加入：

UPDATE e 
      SET e.code = d.code
FROM existingTable e INNER JOIN 
     @declaredTable d
     on d.id = e.id;