oracle递归查询企业互开发票

好的，您的问题是关于Oracle递归查询企业互开发票。

对于这个问题，首先需要明确一下具体的查询需求和数据结构。假设我们有一个名为invoices的表，其中包含了企业之间的开票信息。具体的表结构可能包含以下字段：

- invoice_id: 发票ID
- issuer: 开票企业
- recipient: 收票企业
- amount: 开票金额

现在，我们需要查询企业之间互相开票的情况。这个查询可以使用递归查询来完成。具体步骤如下：

1. 初始化查询条件，找到所有直接互开发票的企业对。

WITH recursive cte_invoices AS (
  SELECT issuer, recipient, amount
  FROM invoices
  WHERE issuer <> recipient
  UNION
  SELECT i1.issuer, i2.recipient, i1.amount + i2.amount
  FROM invoices i1
  JOIN cte_invoices i2 ON i1.recipient = i2.issuer
  WHERE i1.issuer <> i2.recipient
)
SELECT issuer, recipient, SUM(amount) AS total
FROM cte_invoices
GROUP BY issuer, recipient

2. 如果有更多的企业之间存在互开发票的情况，需要继续递归查询。

WITH recursive cte_invoices AS (
  SELECT issuer, recipient, amount
  FROM invoices
  WHERE issuer <> recipient
  UNION
  SELECT i1.issuer, i2.recipient, i1.amount + i2.amount
  FROM invoices i1
  JOIN cte_invoices i2 ON i1.recipient = i2.issuer
  WHERE i1.issuer <> i2.recipient
)
, cte_final AS (
  SELECT issuer, recipient, SUM(amount) AS total
  FROM cte_invoices
  GROUP BY issuer, recipient
)
SELECT * FROM cte_final
UNION
SELECT issuer, recipient, SUM(total) AS total
FROM (
  SELECT DISTINCT issuer, recipient, total
  FROM cte_invoices
  WHERE issuer NOT IN (SELECT recipient FROM cte_final)
) t
GROUP BY issuer, recipient

这样就可以查询出所有企业之间互相开票的情况了。需要注意的是，这个查询可能会比较耗时，具体取决于数据量和递归深度。如果数据量很大，可以考虑添加索引或者分区等优化手段。