Create table from JSON file in PostgreSQL - json

Question

I'm just learning how to use PostgreSQL and JSON. I came across this great tutorial, but the syntax was made for SQL Server. I am trying to take the following JSON file and begin parsing it into a table with columns for squad, name, age, and powers.
The JSON code is
CREATE TABLE heroes (
id serial NOT NULL PRIMARY KEY,
info json NOT NULL
);
insert into heroes (info)
values (('
{
"squadName": "Super hero squad",
"homeTown": "Metro City",
"formed": 2016,
"secretBase": "Super tower",
"active": true,
"members": [
{
"name": "Molecule Man",
"age": 29,
"secretIdentity": "Dan Jukes",
"powers": [
"Radiation resistance",
"Turning tiny",
"Radiation blast"
]
},
{
"name": "Madame Uppercut",
"age": 39,
"secretIdentity": "Jane Wilson",
"powers": [
"Million tonne punch",
"Damage resistance",
"Superhuman reflexes"
]
},
{
"name": "Eternal Flame",
"age": 1000000,
"secretIdentity": "Unknown",
"powers": [
"Immortality",
"Heat Immunity",
"Inferno",
"Teleportation",
"Interdimensional travel"
]
}
]
}
'::json));
I can access the first level info of the JSON with no issue, eg
SELECT info -> 'squadName' AS squad from heroes; or SELECT info -> 'active' AS active from heroes;
However, when trying to dig deeper into the JSON, I end up with a single row, the correct squad name and NULL for member names:
SELECT info -> 'squadName' AS Squad,
info ->'members' ->> 'name' AS Name
from heroes;
The tutorial uses CROSS APPLY OPENJSON(..) to handle this, but I am not sure of what to do in PostgreSQL.
Any help would be appreciated. I am using this as a learning exercise.

Answer 1

You can do a lateral cross join of json_array_elements().
SELECT h.info->>'squadName' AS squad,
m.m->>'name' AS name
FROM heroes h
CROSS JOIN LATERAL json_array_elements(h.info->'members') m
(m);
db<>fiddle
But as a side note: The schema of the JSON looks pretty static to me. You should consider not to abuse JSON but use relational means like (lookup and/or linking) tables and columns instead.