在T-SQL语句中添加所有列的前缀

Given a table "ABC" with columns Col1, Col2 and Col3 it is possible to automatically generate something like the following:

给定具有列Col1，Col2和Col3的表“ABC”，可以自动生成如下内容：

SELECT
Col1 AS 'ABC_Col1', 
Col2 AS 'ABC_Col2',
Col3 AS 'ABC_Col3' 
FROM ABC

I have a table without a fixed set of columns (users are able to append their own columns) where I still need the column prefix (because it is needed in a JOIN/CTE with other tables that also have columns with the names Col1, Col2 etc...)

我有一个没有固定列的表（用户可以附加自己的列），我仍然需要列前缀（因为在JOIN / CTE中需要它与其他表也有名称为Col1，Col2的列等等...）

Therefore I would like to be able to write something like this:

因此，我希望能够写出这样的东西：

SELECT
T0.* AS 'ABC_T.*', 
FROM ABC T0

Which is of course not valid SQL, but can it be done somehow so the "*" columns all get the same prefix?

这当然不是有效的SQL，但它可以以某种方式完成，所以“*”列都获得相同的前缀？

3 个解决方案

#1

This will give you a map of old column names and new column names:

这将为您提供旧列名和新列名的映射：

SELECT syscolumns.name as old_column_name, 'ABC_' + syscolumns.name as new_column_name
   FROM sysobjects 
        JOIN syscolumns ON sysobjects.id = syscolumns.id
   WHERE sysobjects.name = 'ABC'
ORDER BY sysobjects.name,syscolumns.colid

From there it's just some dynamic sql. I'm still playing with it.

从那里它只是一些动态的SQL。我还在玩它。

EDIT

编辑

OK, I ditched that.

好的，我放弃了。

DECLARE @sql varchar(max)
SET @sql = 'SELECT '

DECLARE @old_column_name varchar(50)
DECLARE @getNext CURSOR
SET @getNext = CURSOR FOR 
    SELECT syscolumns.name
       FROM sysobjects 
            JOIN syscolumns ON sysobjects.id = syscolumns.id
       WHERE sysobjects.name = 'ABC'
OPEN @getNext
FETCH NEXT FROM @getNext INTO @old_column_name
WHILE @@fetch_status = 0
BEGIN

    --BUILD DYNAMIC SQL
    SET @sql = @sql + @old_column_name + ' AS ''ABC_' + @old_column_name + ''', '

FETCH NEXT FROM @getNext INTO @old_column_name
END
CLOSE @getNext
DEALLOCATE @getNext

--REMOVE FINAL COMMA AND ADD TABLE
SET @sql = SUBSTRING(@sql, 0, LEN(@sql)) + ' FROM ABC'

exec(@sql)

A) this is terrible performance (because it's a cursor)

A）这是糟糕的表现（因为它是一个光标）

B) I know you're not meant to do work for people on here, but I got carried away.

B）我知道你不打算为这里的人做工，但我被带走了。

C) I considered not even posting this because of how poor of an answer I feel it is, but it's a least an idea.

C）我认为甚至没有发布这个因为我觉得它的答案有多差，但这至少不是一个想法。

#2

You seem confused as to what column aliases do. As you can see in your select clause, you're already only selecting fields from T0 by referencing T0.*. You can still reference those fields as T0.<whatever> later in your query without aliasing the fields, you will just have to refer to them by their full field name, ie, T0.[My Users Suck And Make Really Long Field Names].

您似乎对列别名的作用感到困惑。正如您在select子句中看到的那样，您只能通过引用T0来选择T0中的字段。*。您仍然可以在查询中稍后将这些字段引用为T0。而不对字段进行别名，您只需要通过它们的完整字段名称来引用它们，即T0。[我的用户吮吸并制作非常长的字段名称] 。

EDIT: To be more clear, you can not change the prefix of a field by aliasing it. You can only change the name of it. The prefix of the field is the alias of the table that it comes from.

编辑：更清楚的是，您不能通过别名来更改字段的前缀。您只能更改它的名称。字段的前缀是它来自的表的别名。

#3

I think the only way you'll be able to do this is by creating some dynamic SQL.

我认为你能够做到这一点的唯一方法是创建一些动态SQL。

#1