mysql - 自连接查询 : how to return children and parent row?

Question

我有这张表:

Content:
- id
- parent_id
- slug
- creation_date

parent_id 是指向同一个表 (content.id) 的外键。

我想选择表中所有属于同一个表中 parent_id 的子行的行。我也想返回父行。

现在我有这两个查询，它们都只返回子行:

SELECT a.* 
FROM content a 
JOIN content b ON a.parent_id = b.id
WHERE b.slug = 'some-slug'
ORDER BY creation_date

和:

SELECT content.* 
FROM content 
WHERE content.parent_id = (SELECT id FROM content WHERE slug= 'some-slug')
ORDER BY creation_date

如何返回按 creation_date 排序的子行和父行？

谢谢!

Answer 1

select  child.*
from    Content child
join    Content parent
on      child.parent_id = parent.id
where   parent.slug = 'some-slug'
union all
select  parent.*
from    Content parent
where   parent.slug = 'some-slug'
order by
        creation_date