我的tabla数据如下;
我想根据产品对其进行分组并将其转换为 json 格式。我想要的最终版本如下;
{
"_id" : "prd_1",
"details" : [
{
"_id" : 1,
"product_id" : "prd_1",
"product_name" : "product one",
"sell_price" : 15,
"purchase_price" : 12,
"country" : "usa"
},
{
"_id" : 2,
"product_id" : "prd_1",
"product_name" : "product one",
"sell_price" : 16,
"purchase_price" : 13,
"country" : "canada"
},
]
}
{
"_id" : "prd_2",
"details" : [
{
"_id" : 3,
"product_id" : "prd_2",
"product_name" : "product two",
"sell_price" : 7,
"purchase_price" : 5,
"country" : "china"
},
{
"_id" : 4,
"product_id" : "prd_2",
"product_name" : "product two",
"sell_price" : 10,
"purchase_price" : 12,
"country" : "japan"
},
]
}
我创建了以下查询,但它没有给出我想要的结果。因为我只想一列所有 json 对象。我们如何创建我想要的查询?有可能吗?
select product_id,
json_agg(obj) as details
from (
select product_id, json_build_object(
'_id', _id,
'product_id', product_id,
'product_name', product_name,
'sell_price', sell_price,
'purchase_price', purchase_price,
'country', country
) as obj
from products p) tmp
group by product_id;
最佳答案
你已经很接近了。只需将整个内容包装在另一个 json_agg()
中即可将其合并为一行:
edb=# select jsonb_pretty(json_agg(tb)::jsonb) from (
select _id, json_agg(obj) as details
from (
select product_id as _id, json_build_object(
'_id', _id,
'product_id', product_id,
'product_name', product_name,
'sell_price', sell_price,
'purchase_price', purchase_price,
'country', country
) as obj
from products p) tmp
group by _id) as tb;
jsonb_pretty
------------------------------------------------
[ +
{ +
"_id": "prd_2", +
"details": [ +
{ +
"_id": 3, +
"country": "china", +
"product_id": "prd_2", +
"sell_price": 7, +
"product_name": "product two",+
"purchase_price": 5 +
}, +
{ +
"_id": 4, +
"country": "japan", +
"product_id": "prd_2", +
"sell_price": 12, +
"product_name": "product two",+
"purchase_price": 10 +
} +
] +
}, +
{ +
"_id": "prd_1", +
"details": [ +
{ +
"_id": 1, +
"country": "usa", +
"product_id": "prd_1", +
"sell_price": 15, +
"product_name": "product one",+
"purchase_price": 12 +
}, +
{ +
"_id": 2, +
"country": "canada", +
"product_id": "prd_1", +
"sell_price": 16, +
"product_name": "product one",+
"purchase_price": 13 +
} +
] +
} +
]
(1 row)
关于json - Postgresql group by 查询转换json格式,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/65388455/