在 SELECT 语句（Oracle 数据库）中创建人工主键/人工列

Question

我有一个看起来像这样的 SQL 语句：

SELECT 
    x, AVG(y) AS z
FROM 
    table
UNPIVOT
    (y FOR x
       IN ("COLUMN1" AS 'A',
           "COLUMN1" AS 'B',
           "COLUMN2" AS 'C',
           "COLUMN3" AS 'D',
           "COLUMN4" AS 'E',
           "COLUMN5" AS 'F',
           "COLUMN6" AS 'G'))
GROUP BY 
    x;

是否有可能为 SELECT 语句中的每一行创建一个人工键？我无法添加表的 ID，因为那样我也必须将它添加到 group by 子句中，并且输出将与之前的输出不同......

基本上我需要在我的选择输出中添加一个唯一的数字列。

Answer 1

我没有 Oracle 服务器来测试它，但像这样的东西应该可以工作：

SELECT 
    ROW_NUMBER() OVER(ORDER BY NULL) AS id_num,
    x, AVG(y) AS z
FROM 
    table
UNPIVOT
    (y FOR x
       IN ("COLUMN1" AS 'A',
           "COLUMN1" AS 'B',
           "COLUMN2" AS 'C',
           "COLUMN3" AS 'D',
           "COLUMN4" AS 'E',
           "COLUMN5" AS 'F',
           "COLUMN6" AS 'G'))
GROUP BY 
    x;