如何编写oracle查询以获取一列值的数据

【问题标题】：How to write oracle query to get the data of one column values如何编写oracle查询以获取一列值的数据
【发布时间】：2016-05-22 15:19:03
【问题描述】：

需要帮助编写查询

我有一列的表，值 A、B、C 和 D。

如何编写查询以获得以下结果： AB，AC，AD，BA，BC，BD，...

对此有任何帮助。提前致谢

【问题讨论】：

标签： oracle oracle11g oracle10g

【解决方案1】：

试试：

with x as (
    select 'A' as col from dual
    union all
    select 'B' as col from dual
    union all
    select 'C' as col from dual
    union all
    select 'D' as col from dual
)
select *
from x join x x2 on x.col != x2.col

输出：

COL COL_1
"A" "B"
"A" "C"
"A" "D"
"B" "A"
"B" "C"
"B" "D"
"C" "A"
"C" "B"
"C" "D"
"D" "A"
"D" "B"
"D" "C"

【讨论】：

【解决方案2】：

这个 SQL 应该可以解决问题：

SELECT T1.COL || T2.COL
FROM MY_TABLE T1, MY_TABLE T2
WHERE T1.COL != T2.COL;

这里，MY_TABLE 是您的表格，其中包含 COL 列。

【讨论】：

【解决方案3】：

很酷的答案。这是我的版本，两个答案的组合：

WITH x AS (
  SELECT 'A' AS col FROM dual
  UNION ALL
  SELECT 'B' AS col FROM dual
  UNION ALL 
  SELECT 'C' AS col FROM dual
  UNION ALL
  SELECT 'D' AS col FROM dual
)

SELECT x1.col || x2.col AS xx
FROM x x1 JOIN x x2 ON x1.col <> x2.col

【讨论】：