postgres to get match count when json value matches condition - json

Question

I have a column in my db entitled supers with a JSON element inside.
Below is its structure:
[
{
"name": "Trample",
"category": "evergreen"
},
{
"name": "Spell",
"category": "keyword"
},
{
"name": "Trample token",
"category": "keyword"
},
{
"name": "Cast",
"category": "keyword"
},
{
"name": "Cost",
"category": "keyword"
},
{
"name": "Total",
"category": "keyword"
},
{
"name": "Power",
"category": "keyword"
},
{
"name": "Creature token",
"category": "keyword"
},
{
"name": "Control",
"category": "keyword"
},
{
"name": "Less",
"category": "keyword"
},
{
"name": "Elder",
"category": "cardType"
},
{
"name": "Dinosaur",
"category": "cardType"
},
{
"name": "Creature",
"category": "cardType"
},
{
"name": "Legendary",
"category": "cardType"
},
{
"name": "Cost x Less",
"category": "super"
},
]
I have the following query to get all rows that have similar values:
select name
from all_cards
where exists (select 1
from jsonb_array_elements(supers) f(x)
where x->>'category' = 'keyword'
and x->>'name' in ('Spell', 'Trample token', 'Cast', 'Cost', 'Total', 'Power', 'Creature token', 'Control', 'Less')
having count(*)>=8);
This query works to get all the names where count(*) >=8 but how do I get that count(*) out as a value, so I can sort the results based on that number?
I've tried jsonb_array_length, count, sum, nothing seems to be able to give me the answer I'm looking for.

Answer 1

You can do a cross join to get the count:
select ac.name, k.num_keywords
from all_cards ac
cross join lateral (
select count(*) as num_keywords
from jsonb_array_elements(ac.supers) f(x)
where x->>'category' = 'keyword'
and x->>'name' in ('Spell', 'Trample token', 'Cast', 'Cost', 'Total', 'Power', 'Creature token', 'Control', 'Less')
) k
where k.num_keywords >= 8