Question

我有一个查询，从下面的表

创建一个H_TREE列

+------+--------+
| UNIT | M_UNIT |
+------+--------+
|   10 |     12 |
|   15 |     19 |
|   12 |     16 |
|   13 |     15 |
|   19 |     14 |
|   14 |     11 |
+------+--------+

以下是我正在使用的查询，

WITH data (unit, m_unit) AS (
  SELECT 10, 12 FROM dual UNION ALL
  SELECT 15, 19 FROM dual UNION ALL
  SELECT 12, 16 FROM dual UNION ALL
  SELECT 13, 15 FROM dual UNION ALL
  SELECT 19, 14 FROM dual UNION ALL
  SELECT 14, 11 FROM dual)
SELECT
    unit,
    m_unit,
    unit || ',' || listagg(root_unit, ',') WITHIN GROUP (ORDER BY depth) h_tree
FROM (
SELECT
    id, unit, m_unit,
    LEVEL depth, CONNECT_BY_ROOT m_unit root_unit
FROM
    (SELECT ROWNUM id, unit, m_unit FROM data) data
CONNECT BY
    PRIOR unit = m_unit)
GROUP BY
    id,
    unit,
    m_unit

上面的查询返回

+------+--------+----------------+
| UNIT | M_UNIT |     H_TREE     |
+------+--------+----------------+
|   10 |     12 | 10,12,16       |
|   15 |     19 | 15,19,14,11    |
|   12 |     16 | 12,16          |
|   13 |     15 | 13,15,19,14,11 |
|   19 |     14 | 19,14,11       |
|   14 |     11 | 14,11          |
+------+--------+----------------+

我想颠倒H_TREE列的顺序，以便它如下所示，

+------+--------+----------------+
| UNIT | M_UNIT |     H_TREE     |
+------+--------+----------------+
|   10 |     12 | 16,12,10       |
|   15 |     19 | 11,14,19,15    |
|   12 |     16 | 16,12          |
|   13 |     15 | 11,14,19,15,13 |
|   19 |     14 | 11,14,19       |
|   14 |     11 | 11,14          |
+------+--------+----------------+

为了实现这一目标，我需要对此现有查询进行哪些更改？

根据评论：WITHIN GROUP（ORDER BY depth DESC）给出了以下结果，

+------+--------+----------------+
| UNIT | M_UNIT |     H_TREE     |
+------+--------+----------------+
| 10   |  12    |  10,16,12      |
| 15   |  19    |  15,11,14,19   |
| 12   |  16    |  12,16         |
| 13   |  15    |  13,11,14,19,15|
| 19   |  14    |  19,11,14      |
| 14   |  11    |  14,11         |
+------+--------+----------------+

Answer 1

尝试：

WITH data (unit, m_unit) AS (
    SELECT 10, 12 FROM dual UNION ALL
    SELECT 15, 19 FROM dual UNION ALL
    SELECT 12, 16 FROM dual UNION ALL
    SELECT 13, 15 FROM dual UNION ALL
    SELECT 19, 14 FROM dual UNION ALL
    SELECT 14, 11 FROM dual)
SELECT
    unit,
    m_unit,
    listagg(root_unit, ',') WITHIN GROUP (ORDER BY depth desc) || ',' || unit as h_tree
FROM (
    SELECT
        id, unit, m_unit,
        LEVEL depth, CONNECT_BY_ROOT m_unit root_unit
    FROM
        (SELECT ROWNUM id, unit, m_unit FROM data) data
    CONNECT BY
        PRIOR unit = m_unit)
GROUP BY
    id,
    unit,
    m_unit

反转存储层次结构的逗号分隔列

为了实现这一目标，我需要对此现有查询进行哪些更改？

1 个答案: