从 Postgres 中的 json 对象中提取键、值

I have a Postgres table that has content similar to this:

id  | data

1   | {"a":"4", "b":"5"}
2   | {"a":"6", "b":"7"}
3   | {"a":"8", "b":"9"}

第一列是整数，第二列是json列.

I want to be able to expand out the keys and values from the json so the result looks like this:

id  | key  | value

1   | a    | 4
1   | b    | 5
2   | a    | 6
2   | b    | 7
3   | a    | 8
3   | b    | 9

Can this be achieved in Postgres SQL?

What I've tried

Given that the original table can be simulated as such:

select *
from 
(
values
(1, '{"a":"4", "b":"5"}'::json),
(2, '{"a":"6", "b":"7"}'::json),
(3, '{"a":"8", "b":"9"}'::json)
) as q (id, data)

我可以通过以下方式获得 keys :

select id, json_object_keys(data::json)
from 
(
values
(1, '{"a":"4", "b":"5"}'::json),
(2, '{"a":"6", "b":"7"}'::json),
(3, '{"a":"8", "b":"9"}'::json)
) as q (id, data)

我可以把它们做成创纪录的唱片，就像这样:

select id, json_each(data::json)
from 
(
values
(1, '{"a":"4", "b":"5"}'::json),
(2, '{"a":"6", "b":"7"}'::json),
(3, '{"a":"8", "b":"9"}'::json)
) as q (id, data)

但我不知道如何用id、key和value实现这个结果.

有什么 idea 吗？

Note: the real json I'm working with is significantly more nested than this, but I think this example represents my underlying problem well.