javascript - select 返回零行，尽管它应该返回一些条目

Question

我有一个 postgres 数据库，代表一个简单的演示论坛。有两个表称为

主题

id   | topic_id (the parent topic) | name | description
-------------------------------------------------------
uuid | uuid                        | text | text

和话题

id   | topic_id | name | created_at
-------------------------------------------------------
uuid | uuid     | text | timestamp without timezone

通过使用 Express REST API，我想获取一个主题的所有信息。我传入它的 ID，并希望得到这样的结果

{
    parentTopic: {}, // could be null if no parent is available
    name: "",
    description: "",
    childTopics: [{}, {}, {}],
    threads: [{}, {}, {}] // should be sorted by created_at
}

据我所知，不可能返回这样的结果。但我尝试创建一个查询来获取这些信息，也许我可以稍后用一些代码来映射它。

SELECT
    currentTopic.name,
    currentTopic.description,
    parentTopic.id AS parentTopicId,
    parentTopic.name AS parentTopicName,
    parentTopic.description AS parentTopicDescription,
    childTopic.id AS childTopicId,
    childTopic.name AS childTopicName,
    childTopic.description AS childTopicDescription,
    linkedThread.id AS threadId,
    linkedThread.name AS threadName,
    linkedThread.created_at AS threadCreatedAt
FROM
    topic currentTopic
INNER JOIN
    topic parentTopic ON currentTopic.topic_id = parentTopic.id
INNER JOIN
    topic childTopic ON currentTopic.id = childTopic.topic_id
INNER JOIN
    thread linkedThread ON currentTopic.id = linkedThread.topic_id
WHERE
    currentTopic.id = '624aaab6-2d2d-45dc-a425-c2863f05779c'
ORDER BY
    linkedThread.created_at;

执行此操作时(我使用 pgAdmin)，没有发生错误，但返回了 0 行。我确定，应该有一些条目需要检索。

该查询有问题吗？有没有办法改进查询以返回可供使用的结果(我上面提到的 JS 对象)？

编辑:

这是线程和主题的一些测试数据

主题表:

线程表:

Answer 1

将内连接更改为左连接

SELECT
    currentTopic.name,
    currentTopic.description,
    parentTopic.id AS parentTopicId,
    parentTopic.name AS parentTopicName,
    parentTopic.description AS parentTopicDescription,
    childTopic.id AS childTopicId,
    childTopic.name AS childTopicName,
    childTopic.description AS childTopicDescription,
    linkedThread.id AS threadId,
    linkedThread.name AS threadName,
    linkedThread.created_at AS threadCreatedAt
FROM
    topic currentTopic
left JOIN
    topic parentTopic ON currentTopic.topic_id = parentTopic.id
left JOIN
    topic childTopic ON currentTopic.id = childTopic.topic_id
left JOIN
    thread linkedThread ON currentTopic.id = linkedThread.topic_id
WHERE
    currentTopic.id = '624aaab6-2d2d-45dc-a425-c2863f05779c'
ORDER BY
    linkedThread.created_at;