Postgres jsonb заявка за вложен обект

Използвайте json_agg() и jsonb_array_elements() функции:

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

Можете да обедините две вътрешни подзаявки:

select json_agg(cell)
from (
    select jsonb_array_elements(jsonb_array_elements(data->'cust')->'cell') cell
    from product_cust
    ) sub

Групирайте резултатите по productid:

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