按键/值过滤 JSON 数组元素的 PostgreSQL (v9.6) 查询

Question

We have a jsonb column with data of the type:

"basket": {
    "total": 6,
    "items": [
        {    "type": "A",    "name": "A",    "price": 1    },
        {    "type": "A",    "name": "B",    "price": 2    },
        {    "type": "C",    "name": "C",    "price": 3    },
    ] 
}

We need to construct few queries that will filter specific elements of the items[] array for SELECT and SUM .

We have PG v9.6 so using jsonb_path_query_array didn't work.

Using basket->'items' @> '{"type":"A"}' works to find all entries that has type-A.

But how do we get subquery to

• select only basket items of type-A
• sum of prices of items of type-A

Thank you!

Answer 1

This will select the required items:

select * from jsonb_array_elements('{"basket": 
{
    "total": 6,
    "items": [
        {    "type": "A",    "name": "A",    "price": 1    },
        {    "type": "A",    "name": "B",    "price": 2    },
        {    "type": "C",    "name": "C",    "price": 3    }
    ] 
}}'::jsonb#>'{basket,items}') e(it)
where it->>'type' = 'A';

and this the sum of prices:

select sum(cast(it->>'price' as numeric)) from  jsonb_array_elements('{"basket": 
{
    "total": 6,
    "items": [
        {    "type": "A",    "name": "A",    "price": 1    },
        {    "type": "A",    "name": "B",    "price": 2    },
        {    "type": "C",    "name": "C",    "price": 3    }
    ] 
}}'::jsonb#>'{basket,items}') e(it)
where it->>'type' = 'A';