为 T-SQL 语句中的所有列添加前缀 [英] Prefix all columns in T-SQL statement

问题描述

给定一个包含 Col1、Col2 和 Col3 列的ABC"表，可以自动生成如下内容:

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

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

我有一个没有固定列集的表(用户可以附加他们自己的列)，我仍然需要列前缀(因为在 JOIN/CTE 中需要它，其他表也有带有名称的列Col1, Col2 等...)

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...)

因此我希望能够写出这样的东西:

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

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

这当然不是有效的 SQL，但可以以某种方式完成，以便*"列都获得相同的前缀?

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

推荐答案

这将为您提供旧列名称和新列名称的映射:

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

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

从那里开始，它只是一些动态 sql.我还在玩它.

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

编辑

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) 这是糟糕的表现(因为它是一个游标)

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

B) 我知道你不打算为这里的人工作，但我被冲昏了头脑.

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

C) 我什至考虑过不发布这个，因为我觉得它的答案很糟糕，但这至少是一个想法.

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.

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