Question

我有一个更大的SQL，它产生与此简化示例类似的输出：

SELECT
  5 AS L0,
  2 AS L1,
  3 AS L2,
  4 AS L3
FROM DUAL

当前输出是这一行：

| L0 | L1 | L2 | L3 |
|  5 |  2 |  3 |  4 |

所需的输出是此列：

| kind | value |
|   0  |   5   |
|   1  |   2   |
|   2  |   3   |
|   3  |   4   |

我知道我可以通过4次联合选择得到这个。如果工会是我能在这里做的最好的，如果这个输出可以通过其他方式实现，我正在寻求建议。

我还发现了许多将列反转为行的示例，但我在这里寻找从行到列的反转。

Answer 1

请尝试UnPIVOT：

SELECT substr(kind,2,1) AS kind,"value" FROM 
(    
    SELECT
        5 AS l0,
        2 AS l1,
        3 AS l2,
        4 AS l3
    FROM dual
)temp unpivot include NULLS ("value" FOR kind IN (l0, l1 , l2, l3));

相反地：

 SELECT *   
 FROM 
 (
      SELECT Kind,
             max(Value) Value
      FROM table 
      GROUP BY Kind
 ) PIVOT ( max(Value) FOR Kind IN (L0, L1, L2, L3) );

假设您确实有一个要查询的表。

Answer 2

select i - 1 kind,

    case when i = 1 then L0
         when i = 2 then L1
         when i = 3 then L2
         when i = 4 then L3
     end  as value
  from your_table,
       (select level as i from dual connect by level <= 4)

这会产生你桌子上的Carteasan产品和“内联视图”。内联视图将输出四行，1到4.

反行到列

2 个答案: