SQL oracle 将列转换为一对 column_name/value

Question

基本上我正在做这个测试 table :

dog         cat          snake
------------------------------
 5           7             7
 9           8             5
 1           3             7

我想通过 SQL 请求将其转换为：

    column_name           value
    ---------------------------
     dog                    5
     cat                    7
     snake                  7
     dog                    9
      ..                    ..

我不知道我可以使用哪个 Oracle SQL 函数来实现这一点，我听说过 Pivot，但我不知道它在这种情况下如何工作。

Answer 1

您可以使用 union all :

select 'dog' as col, dog
from table t
union all
select 'cat', cat
from table t
union all
select 'snake', snake
from table t;

Answer 2

使用UNPIVOT:

SQL Fiddle

Oracle 11g R2 架构设置:

CREATE TABLE table_name (dog, cat, snake) AS
SELECT 5, 7, 7 FROM DUAL UNION ALL
SELECT 9, 8, 5 FROM DUAL UNION ALL
SELECT 1, 3, 7 FROM DUAL;

查询 1:

SELECT *
FROM   table_name
UNPIVOT(
  value FOR column_name IN ( dog, cat, snake )
)

Results:

| COLUMN_NAME | VALUE |
|-------------|-------|
|         DOG |     5 |
|         CAT |     7 |
|       SNAKE |     7 |
|         DOG |     9 |
|         CAT |     8 |
|       SNAKE |     5 |
|         DOG |     1 |
|         CAT |     3 |
|       SNAKE |     7 |

SQL oracle 将列转换为一对 column_name/value

SQL oracle convert columns to a pair column_name/value

sql

oracle

pivot

unpivot