On Tue, 16 Jul 2019 at 19:44, Alexander Korotkov <a.korot...@postgrespro.ru> wrote: > > On Tue, Jul 16, 2019 at 9:22 PM Thom Brown <t...@linux.com> wrote: > > Now I'm looking at the @? and @@ operators, and getting a bit > > confused. This following query returns true, but I can't determine > > why: > > > > # SELECT '{"a":[1,2,3,4,5]}'::jsonb @? '$.b == "hello"'::jsonpath; > > ?column? > > ---------- > > t > > (1 row) > > > > "b" is not a valid item, so there should be no match. Perhaps it's my > > misunderstanding of how these operators are supposed to work, but the > > documentation is quite terse on the behaviour. > > So, the result of jsonpath evaluation is single value "false". > > # SELECT jsonb_path_query_array('{"a":[1,2,3,4,5]}'::jsonb, '$.b == "hello"'); > jsonb_path_query_array > ------------------------ > [false] > (1 row) > > @@ operator checks that result is "true". This is why it returns "false". > > @? operator checks if result is not empty. So, it's single "false" > value, not empty list. This is why it returns "true". > > Perhaps, we need to clarify this in docs providing more explanation.
Understood. Thanks. Also, is there a reason why jsonb_path_query doesn't have an operator analog? Thom