Question

在docs的示例中，可以使用WITH RECURSIVE查询由具有父ID的行组成的树。

CREATE TABLE org(
  name TEXT PRIMARY KEY,
  boss TEXT REFERENCES org
);

提供的示例是后代查询（即为节点及其所有子节点执行此操作）：

WITH RECURSIVE
  works_for_alice(n) AS (
    VALUES('Alice')
    UNION
    SELECT name FROM org, works_for_alice
     WHERE org.boss=works_for_alice.n
  )
SELECT avg(height) FROM org
 WHERE org.name IN works_for_alice;

相反的例子是什么：具体来说：Alice up 的命令链直到Boss为空（即根节点）？与示例相反，我只需要一个结果列表，而不是进一步处理。

Answer 1

WITH RECURSIVE
  works_for_alice(n) AS (
    VALUES('Alice')
    UNION
    SELECT boss FROM org WHERE name=n AND boss IS NOT NULL
  )
SELECT avg(height) FROM org
 WHERE org.name IN works_for_alice;

SQLite递归CTE，查询一个层次结构

1 个答案: