Iterate over JSON object keys and values with jq

Question

Here is jq getting field a1:

$ echo '{"a": {"a1": 1}, "b": {"a1": 2}}' | jq -r ".[] | .a1"
1
2

I'd like to get the keys a and b as well, and output a flat result, i.e.

$ echo '{"a": {"a1": 1}, "b": {"a1": 2}}' | jq -r "<magic here>"
a 1
b 2

Suggestions?

Answer 1

I guess I found an answer:

$ echo '{"a": {"a1": 1}, "b": {"a1": 2}}' | \
   jq -r 'to_entries[] | [.key, .value.a1] | @tsv'
a   1
b   2

Answer 2

Here's an alternative using keys (or keys_unsorted):

$ echo '{"a": {"a1": 1}, "b": {"a1": 2}}' |
   jq -r 'keys[] as $key | [$key, .[$key].a1] | @tsv'
a   1
b   2