Question

需要帮助才能编写查询

我有一列有一列，有值A，B，C＆amp; D.

如何编写查询以获得以下结果： AB，AC，AD，BA，BC，BD，......

对此有任何身体帮助。提前致谢

Answer 1

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"

Answer 2

这个SQL可以解决这个问题：

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

此处，MY_TABLE是包含COL列的表格。

Answer 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

如何编写oracle查询来获取一列值的数据

3 个答案: