如果我选择某个内容作为名称，然后选择其他内容作为相同名称，会发生什么情况？
我已经回答了我的问题，但在这里没有看到，所以我们开始吧。如果问题已被准确询问，请随时链接到该问题。 我将问题简化为以下代码：
SELECT 'a' AS col1, 'b' AS col1
这会产生相同的列名错误吗？
是否总是返回最后一个值，或者 col1 是否有可能是“a”？
I've already answered my question but didn't see it on here, so here we go. Please feel free to link to the question if it has been asked exactly.
I simplified my question to the following code:
SELECT 'a' AS col1, 'b' AS col1
Will this give a same column name error?
Will the last value always be returned or is there a chance col1 could be 'a'?
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我不知道为什么你会想要这个，但我在 Oracle (10g) 中尝试过，它工作得很好，返回了两列。我知道您专门询问过有关 SQL Server 的问题，但我发现这确实有效，这很有趣。
编辑：它也适用于 MySQL。
I'm not sure why you would ever want this, but I tried it in Oracle (10g) and it worked fine, returning both columns. I realize you've asked about SQL Server specifically, but I found it interesting that this worked at all.
Edit: It also works on MySQL.
它适用于最终查询：
但是，当您在子选择中执行此操作并引用不明确的列别名时在外部查询中，您会收到错误：
It works in the final query:
However when you do it in a subselect and refer to the ambiguous column aliases in an outer query you get an error:
在
SQL 2008 r2中，它作为独立查询有效。在某些情况下，它会产生错误（不完整列表）：内联视图
公用表条目
存储过程（当输出由报告服务使用时）大概类似的集成工具
很难想象您会想要重复的行名称，而且很容易想到现在使用重复编写查询的方式将来可能会变得糟糕。
In
SQL 2008 r2it is valid as a stand alone query. Under certain circumstances it will produce errors (incomplete list):Inline views
Common Table Entries
Stored Procedures when the output is used by reporting services and presumably similarly integrated tools
It's hard to imagine a case where you would want duplicate row names, and it's easy to think of ways in which writing queries with repeats now could turn sour in the future.