sql - PostgreSQL : Building a nested json structure on a single table?

Question

我正在尝试从单个表构建嵌套的 Json 结构。

我试图让最终结果看起来像:

[
    {
        "contract_number":"GS00F0XXX",
        'category': [
            {
                'cat_id': "874 1",
                'socio': {
                    "eighta":false,
                    "sdvosb":false,
                    "edwosb":false
                }   
            },
            {
                "cat_id":"874 6",
                'socio': {
                    "eighta":false,
                    "sdvosb":false,
                    "edwosb":false,
                }
            }
        ]
    },
    {
        'contract_number': "GS00Q14OAXXX",
        'category': [
            {
                'cat_id': 'OASIS POOL1',
                'socio': ...
            }
        ]
    }  
]

底层表看起来像这样:

contract_type   contract_number duns_number eighta  sdvosb  edwosb  category
MOBIS           GS00F0XXX       5555555     FALSE   FALSE   FALSE   874 1
MOBIS           GS00F0XXX       5555555     FALSE   FALSE   FALSE   874 6
MOBIS           GS00F0XXX       5555555     FALSE   FALSE   FALSE   874 7
OASIS           GS00Q14OAXXX    5555555     FALSE   FALSE   FALSE   OASIS POOL1
OASIS           GS00Q14OAXXX    5555555     FALSE   FALSE   FALSE   OASIS POOL2

我试过这个查询，但它把所有东西都放在两行上，每次我尝试嵌套 json_agg 调用时，我都会收到有关 nestng 聚合函数的错误。

select 
    json_build_object(
        'contract_number', contract_number,
        'info', json_agg(
            json_build_object(
                    'category_id', category,
                    'eighta',eighta,
                    'sdvosb',sdvosb,
                    'edwosb',edwosb
                )
        )
    )
from contract_vehicle
group by duns_number, contract_number

这导致 SQL 错误 [42803]:错误:聚合函数调用不能嵌套

select 
    json_build_object(
        'contract_number', contract_number,
        'info', json_agg(
            json_build_object(
                    'category_id', category,
                    'socio', jsonb_agg(
                        json_build_object(
                            'eighta',eighta,
                            'sdvosb',sdvosb,
                            'edwosb',edwosb
                        )
                    )
                )
        )
    )
from contract_vehicle
group by duns_number, contract_number 

Answer 1

我不确定这是否有效，但试一试 :)

with cte as (
    select  json_agg(
                        json_build_object(
                            'eighta',eighta,
                            'sdvosb',sdvosb,
                            'edwosb',edwosb
                        )
                    ) a1,duns_number dn, contract_number cn
    from contract_vehicle
    group by duns_number, contract_number)
select json_build_object(
        'contract_number'::text, contract_number::text,
        'info'::text, json_agg(
            json_build_object(
                    'category_id'::text, category::text,
                    'socio'::text, a1
                )
        )
    )
from contract_vehicle inner join cte on (duns_number=dn and contract_number = cn)
group by duns_number, contract_number;