Postgres GROUP BY on jsonb inner field

Question

I am using Postgresql 9.4 and have a table test, with id::int and content::jsonb, as follows:

Answer 1

You have to use the #>> operator instead of ->> when the right operand is a json path. Try this:

SELECT json_agg(content) as content FROM test GROUP BY content #>> '{a,b}';

Yields:

              content
------------------------------------
 [{"a": {"c": 1}}]
 [{"a": {"b": 2}}]
 [{"a": {"b": 1}}, {"a": {"b": 1}}]
(3 rows)