如何编写oracle查询以获取单列值的数据

需要帮助来编写查询吗

我有一个表，有一列，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

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任何人都可以帮忙。提前感谢

此SQL应该可以实现以下功能：

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

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这里，MY_TABLE是带有列COL的表。

此SQL应该可以实现以下功能：

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

这里，MY_TABLE是您的列列为COL的表。

请尝试：

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"

尝试：

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"

---

冷静的回答。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

---

冷静的回答。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