Gebruik json_agg() en jsonb_array_elements() functies:
select json_agg(cell)
from (
select jsonb_array_elements(elem->'cell') cell
from (
select jsonb_array_elements(data->'cust') elem
from product_cust
) subsub
) sub
U kunt twee innerlijke subquery's samenvoegen:
select json_agg(cell)
from (
select jsonb_array_elements(jsonb_array_elements(data->'cust')->'cell') cell
from product_cust
) sub
Groepeer resultaten op product-ID:
select productid, json_agg(cell)
from (
select productid, jsonb_array_elements(jsonb_array_elements(data->'cust')->'cell') cell
from product_cust
) sub
group by 1
order by 1