Postgresql join on jsonb array - json

Question

I'm new to JSONB and I am wondering, if the following would be possible with a single query:
I have a lot of tables that look like this:
ID (INT) | members (JSONB)
all the tables has only one row.
example for 2 tables
table1:
id: 1
data:
[
{
"computer": "12.12.12.12",
"tag": "dog"
},
{
"computer": "1.1.1.1",
"tag": "cat"
},
{
"computer": "2.2.2.2",
"tag": "cow"
}
]
table2:
id: 1
data:
[
{
"IP address": "12.12.12.12",
"name": "Beni",
"address": "Rome"
},
{
"IP address": "1.1.1.1",
"name": "Jone",
"address": "Madrid"
}
]
The result should be rows like this :
computer
tag
name
12.12.12.12
dog
Beni
1.1.1.1
cat
Jone
Thanks !

Answer 1

Convert jsons into setof types using jsonb_to_recordset function and then join them (like they were relational tables).
with table1 (id,members) as (
values (1,'[{"computer": "12.12.12.12","tag": "dog"},{"computer": "1.1.1.1","tag": "cat"},{"computer": "2.2.2.2","tag": "cow"}]'::jsonb)
), table2 (id,members) as (
values (1,'[{"IP address": "12.12.12.12","name": "Beni", "address": "Rome"},{"IP address": "1.1.1.1","name": "Jone", "address": "Madrid"}]'::jsonb)
)
select t1.computer, t1.tag, t2.name
from jsonb_to_recordset((select members from table1 where id=1)) as t1(computer text,tag text)
join jsonb_to_recordset((select members from table2 where id=1)) as t2("IP address" text,name text)
on t1.computer = t2."IP address"
db fiddle

Answer 2

to get values out of a jsonb array of objects you somehow have to explode them.
another way with jsonb_array_elements:
with _m as (
select
jsonb_array_elements(members.data) as data
from members
),
_m2 as (
select
jsonb_array_elements(members2.data) as data
from members2
)
select
_m.data->>'computer' as computer,
_m.data->>'tag' as tag,
_m2.data->>'name' as name
from _m
left join _m2 on _m2.data->>'IP address' = _m.data->>'computer'
https://www.db-fiddle.com/f/68iC5TzLKbzkLZ8gFWYiLz/0