Question

我有一个巨大的sql查询，其中有以下选择行：

COALESCE(JSONB_AGG(JSONB_BUILD_OBJECT('id', tiw.topicwordid, 'topic', tw.topic, 'wikilink', tw.wikilink)) FILTER (WHERE tiw.topicwordid IS NOT NULL), '[]') as TopicWords

在我的JSON_BUILD_OBJECT里面，我想有一列“计数”。在这里，我想对一个对象在下面的列表中发生多少次进行计数。然后，我想区分该列表，以便每个对象仅出现一次。现在的结果如下：

  [{
        "topic": "Automotive technologies",
        "wikilink": "http://en.wikipedia.org/Category:Automotive_technologies",
        "id": 1411
    },{
        "topic": "Government incentives for plug-in electric vehicles",
        "wikilink": "http://en.wikipedia.org/Government_incentives_for_plug-in_electric_vehicles",
        "id": 1412
    },{
        "topic": "Electric car",
        "wikilink": "http://en.wikipedia.org/Electric_car",
        "id": 932
    },{
        "topic": "Electric vehicle manufacturers",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicle_manufacturers",
        "id": 1413
    },{
        "topic": "Cars",
        "wikilink": "http://en.wikipedia.org/Category:Cars_by_country",
        "id": 1414
    },{
        "topic": "Electric vehicle industry",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicle_industry",
        "id": 1415
    },{
        "topic": "Automobiles",
        "wikilink": "http://en.wikipedia.org/Category:Automobiles",
        "id": 1084
    },{
        "topic": "Transport",
        "wikilink": "http://en.wikipedia.org/Category:Transport",
        "id": 939
    },{
        "topic": "Wheeled vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Wheeled_vehicles",
        "id": 1408
    },{
        "topic": "Tesla Model S",
        "wikilink": "http://en.wikipedia.org/Tesla_Model_S",
        "id": 1476
    },{
        "topic": "Motor vehicle manufacturers",
        "wikilink": "http://en.wikipedia.org/Category:Motor_vehicle_manufacturers",
        "id": 1425
    },{
        "topic": "Electric vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicles",
        "id": 1402
    },{
        "topic": "Automobile models",
        "wikilink": "http://en.wikipedia.org/Category:Automobile_models",
        "id": 1427
    },{
        "topic": "Aerodynamics",
        "wikilink": "http://en.wikipedia.org/Aerodynamics",
        "id": 1886
    },{
        "topic": "Product introductions",
        "wikilink": "http://en.wikipedia.org/Category:Product_introductions_by_year",
        "id": 1517
    },{
        "topic": "Sports cars",
        "wikilink": "http://en.wikipedia.org/Category:Sports_cars",
        "id": 1423
    },{
        "topic": "Sedans",
        "wikilink": "http://en.wikipedia.org/Category:Sedans",
        "id": 1436
    },{
        "topic": "Artificial objects",
        "wikilink": "http://en.wikipedia.org/Category:Artificial_objects",
        "id": 1030
    },{
        "topic": "Private transport",
        "wikilink": "http://en.wikipedia.org/Category:Private_transport",
        "id": 1400
    },{
        "topic": "Automotive technologies",
        "wikilink": "http://en.wikipedia.org/Category:Automotive_technologies",
        "id": 1411
    },{
        "topic": "Vehicle technology",
        "wikilink": "http://en.wikipedia.org/Category:Vehicle_technology",
        "id": 1407
    },{
        "topic": "Transportation engineering",
        "wikilink": "http://en.wikipedia.org/Category:Transportation_engineering",
        "id": 1273
    },{
        "topic": "Car body styles",
        "wikilink": "http://en.wikipedia.org/Category:Car_body_styles",
        "id": 1419
    },{
        "topic": "Transport",
        "wikilink": "http://en.wikipedia.org/Category:Transport",
        "id": 939
    },{
        "topic": "Automobile layouts",
        "wikilink": "http://en.wikipedia.org/Category:Automobile_layouts",
        "id": 1420
    },{
        "topic": "Land vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Land_vehicles",
        "id": 1410
    },{
        "topic": "Wheeled vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Wheeled_vehicles",
        "id": 1408
    },{
        "topic": "Automotive industry",
        "wikilink": "http://en.wikipedia.org/Category:Automotive_industry",
        "id": 1403
    },{
        "topic": "Vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Vehicles",
        "id": 1401
    },{
        "topic": "Motor vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Motor_vehicles",
        "id": 1086
    },{
        "topic": "Automobiles",
        "wikilink": "http://en.wikipedia.org/Category:Automobiles",
        "id": 1084
    },{
        "topic": "Rear-wheel-drive vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Rear-wheel-drive_vehicles",
        "id": 1712
    },{
        "topic": "Electric vehicle manufacturers",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicle_manufacturers",
        "id": 1413
    },{
        "topic": "Cars of the United States",
        "wikilink": "http://en.wikipedia.org/Category:Cars_of_the_United_States",
        "id": 1710
    },{
        "topic": "Cars",
        "wikilink": "http://en.wikipedia.org/Category:Cars_by_country",
        "id": 1414
    },{
        "topic": "Tesla Model S",
        "wikilink": "http://en.wikipedia.org/Tesla_Model_S",
        "id": 1476
    },{
        "topic": "Fuel economy in automobiles",
        "wikilink": "http://en.wikipedia.org/Fuel_economy_in_automobiles",
        "id": 1749
    },{
        "topic": "Tesla, Inc.",
        "wikilink": "http://en.wikipedia.org/Tesla,_Inc.",
        "id": 1444
    },{
        "topic": "Car",
        "wikilink": "http://en.wikipedia.org/Car",
        "id": 1457
    },{
        "topic": "Charging station",
        "wikilink": "http://en.wikipedia.org/Charging_station",
        "id": 1736
    },{
        "topic": "Technology",
        "wikilink": "http://en.wikipedia.org/Category:Technology",
        "id": 1066
    },{
        "topic": "Private transport",
        "wikilink": "http://en.wikipedia.org/Category:Private_transport",
        "id": 1400
    },{
        "topic": "Energy",
        "wikilink": "http://en.wikipedia.org/Energy",
        "id": 1010
    },{
        "topic": "Green vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Green_vehicles",
        "id": 1409
    },{
        "topic": "Automotive technologies",
        "wikilink": "http://en.wikipedia.org/Category:Automotive_technologies",
        "id": 1411
    },{
        "topic": "Manufactured goods",
        "wikilink": "http://en.wikipedia.org/Category:Manufactured_goods",
        "id": 1516
    },{
        "topic": "Artificial objects",
        "wikilink": "http://en.wikipedia.org/Category:Artificial_objects",
        "id": 1030
    },{
        "topic": "Low-carbon economy",
        "wikilink": "http://en.wikipedia.org/Category:Low-carbon_economy",
        "id": 1406
    },{
        "topic": "Land vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Land_vehicles",
        "id": 1410
    },{
        "topic": "Electric power",
        "wikilink": "http://en.wikipedia.org/Category:Electric_power",
        "id": 1071
    },{
        "topic": "Vehicle electrification",
        "wikilink": "http://en.wikipedia.org/Category:Vehicle_electrification",
        "id": 1405
    },{
        "topic": "Vehicle technology",
        "wikilink": "http://en.wikipedia.org/Category:Vehicle_technology",
        "id": 1407
    },{
        "topic": "Transportation engineering",
        "wikilink": "http://en.wikipedia.org/Category:Transportation_engineering",
        "id": 1273
    },{
        "topic": "Sedans",
        "wikilink": "http://en.wikipedia.org/Category:Sedans",
        "id": 1436
    },{
        "topic": "Sports cars",
        "wikilink": "http://en.wikipedia.org/Category:Sports_cars",
        "id": 1423
    },{
        "topic": "Electric vehicle industry",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicle_industry",
        "id": 1415
    },{
        "topic": "Automobiles",
        "wikilink": "http://en.wikipedia.org/Category:Automobiles",
        "id": 1084
    },{
        "topic": "Vehicle electrification",
        "wikilink": "http://en.wikipedia.org/Category:Vehicle_electrification",
        "id": 1405
    },{
        "topic": "Motor vehicle manufacturers",
        "wikilink": "http://en.wikipedia.org/Category:Motor_vehicle_manufacturers",
        "id": 1425
    },{
        "topic": "Zero-emissions vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Zero-emissions_vehicles",
        "id": 1404
    },{
        "topic": "Car body styles",
        "wikilink": "http://en.wikipedia.org/Category:Car_body_styles",
        "id": 1419
    },{
        "topic": "Automobile layouts",
        "wikilink": "http://en.wikipedia.org/Category:Automobile_layouts",
        "id": 1420
    },{
        "topic": "Luxury motor vehicle manufacturers",
        "wikilink": "http://en.wikipedia.org/Category:Luxury_motor_vehicle_manufacturers",
        "id": 1424
    },{
        "topic": "Electric vehicle manufacturers",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicle_manufacturers",
        "id": 1413
    },{
        "topic": "Cars",
        "wikilink": "http://en.wikipedia.org/Category:Cars_by_country",
        "id": 1414
    },{
        "topic": "Automotive technologies",
        "wikilink": "http://en.wikipedia.org/Category:Automotive_technologies",
        "id": 1411
    },{
        "topic": "Vehicle technology",
        "wikilink": "http://en.wikipedia.org/Category:Vehicle_technology",
        "id": 1407
    },{
        "topic": "Luxury vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Luxury_vehicles",
        "id": 1422
    },{
        "topic": "Electric vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicles",
        "id": 1402
    },{
        "topic": "Transportation engineering",
        "wikilink": "http://en.wikipedia.org/Category:Transportation_engineering",
        "id": 1273
    },{
        "topic": "Transport",
        "wikilink": "http://en.wikipedia.org/Category:Transport",
        "id": 939
    },{
        "topic": "Land vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Land_vehicles",
        "id": 1410
    },{
        "topic": "Wheeled vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Wheeled_vehicles",
        "id": 1408
    },{
        "topic": "Automotive industry",
        "wikilink": "http://en.wikipedia.org/Category:Automotive_industry",
        "id": 1403
    },{
        "topic": "Motor vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Motor_vehicles",
        "id": 1086
    },{
        "topic": "Vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Vehicles",
        "id": 1401
    },{
        "topic": "Private transport",
        "wikilink": "http://en.wikipedia.org/Category:Private_transport",
        "id": 1400
    },{
        "topic": "Tesla Model S",
        "wikilink": "http://en.wikipedia.org/Tesla_Model_S",
        "id": 1476
    },{
        "topic": "Electric vehicle industry",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicle_industry",
        "id": 1415
    },{
        "topic": "Automobiles",
        "wikilink": "http://en.wikipedia.org/Category:Automobiles",
        "id": 1084
    },{
        "topic": "Zero-emissions vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Zero-emissions_vehicles",
        "id": 1404
    },{
        "topic": "Battery electric vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Battery_electric_vehicles",
        "id": 1514
    },{
        "topic": "Transport",
        "wikilink": "http://en.wikipedia.org/Category:Transport",
        "id": 939
    },{
        "topic": "Elon Musk",
        "wikilink": "http://en.wikipedia.org/Elon_Musk",
        "id": 1468
    },{
        "topic": "Electric vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicles",
        "id": 1402
    },{
        "topic": "Battery electric vehicle manufacturers",
        "wikilink": "http://en.wikipedia.org/Category:Battery_electric_vehicle_manufacturers",
        "id": 1515
    },{
        "topic": "Travis Kalanick",
        "wikilink": "http://en.wikipedia.org/Travis_Kalanick",
        "id": 1714
    },{
        "topic": "Automotive industry",
        "wikilink": "http://en.wikipedia.org/Category:Automotive_industry",
        "id": 1403
    },{
        "topic": "Tesla, Inc.",
        "wikilink": "http://en.wikipedia.org/Tesla,_Inc.",
        "id": 1444
    },{
        "topic": "Electric car",
        "wikilink": "http://en.wikipedia.org/Electric_car",
        "id": 932
    },{
        "topic": "Motor vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Motor_vehicles",
        "id": 1086
    },{
        "topic": "Tesla Model S",
        "wikilink": "http://en.wikipedia.org/Tesla_Model_S",
        "id": 1476
    },{
        "topic": "Electric vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicles",
        "id": 1402
    },{
        "topic": "Vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Vehicles",
        "id": 1401
    },{
        "topic": "Car",
        "wikilink": "http://en.wikipedia.org/Car",
        "id": 1457
    },{
        "topic": "Tesla, Inc.",
        "wikilink": "http://en.wikipedia.org/Tesla,_Inc.",
        "id": 1444
    },{
        "topic": "Charging station",
        "wikilink": "http://en.wikipedia.org/Charging_station",
        "id": 1736
    },{
        "topic": "Land vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Land_vehicles",
        "id": 1410
    },{
        "topic": "Mechanical engineering",
        "wikilink": "http://en.wikipedia.org/Category:Mechanical_engineering",
        "id": 1933
    },{
        "topic": "Transport",
        "wikilink": "http://en.wikipedia.org/Category:Transport",
        "id": 939
    },{
        "topic": "Technology",
        "wikilink": "http://en.wikipedia.org/Category:Technology",
        "id": 1066
    },{
        "topic": "Electric vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicles",
        "id": 1402
    },{
        "topic": "Motor vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Motor_vehicles",
        "id": 1086
    },{
        "topic": "Artificial objects",
        "wikilink": "http://en.wikipedia.org/Category:Artificial_objects",
        "id": 1030
    },{
        "topic": "Manufactured goods",
        "wikilink": "http://en.wikipedia.org/Category:Manufactured_goods",
        "id": 1516
    },{
        "topic": "Automotive industry",
        "wikilink": "http://en.wikipedia.org/Category:Automotive_industry",
        "id": 1403
    },{
        "topic": "Automobiles",
        "wikilink": "http://en.wikipedia.org/Category:Automobiles",
        "id": 1084
    },{
        "topic": "Automotive technologies",
        "wikilink": "http://en.wikipedia.org/Category:Automotive_technologies",
        "id": 1411
    },{
        "topic": "Transportation engineering",
        "wikilink": "http://en.wikipedia.org/Category:Transportation_engineering",
        "id": 1273
    },{
        "topic": "Vehicle technology",
        "wikilink": "http://en.wikipedia.org/Category:Vehicle_technology",
        "id": 1407
    },{
        "topic": "Vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Vehicles",
        "id": 1401
    },{
        "topic": "Wheeled vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Wheeled_vehicles",
        "id": 1408
    },{
        "topic": "Private transport",
        "wikilink": "http://en.wikipedia.org/Category:Private_transport",
        "id": 1400
    },{
        "topic": "Engine",
        "wikilink": "http://en.wikipedia.org/Engine",
        "id": 1504
    },{
        "topic": "Machines",
        "wikilink": "http://en.wikipedia.org/Category:Machines",
        "id": 1934
    },{
        "topic": "Internal combustion engine",
        "wikilink": "http://en.wikipedia.org/Internal_combustion_engine",
        "id": 1935
    },{
        "topic": "Private transport",
        "wikilink": "http://en.wikipedia.org/Category:Private_transport",
        "id": 1400
    },{
        "topic": "Automobiles",
        "wikilink": "http://en.wikipedia.org/Category:Automobiles",
        "id": 1084
    },{
        "topic": "Vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Vehicles",
        "id": 1401
    },{
        "topic": "Electric vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Electric_vehicles",
        "id": 1402
    },{
        "topic": "Automotive industry",
        "wikilink": "http://en.wikipedia.org/Category:Automotive_industry",
        "id": 1403
    },{
        "topic": "Motor vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Motor_vehicles",
        "id": 1086
    },{
        "topic": "Zero-emissions vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Zero-emissions_vehicles",
        "id": 1404
    },{
        "topic": "Vehicle electrification",
        "wikilink": "http://en.wikipedia.org/Category:Vehicle_electrification",
        "id": 1405
    },{
        "topic": "Transport",
        "wikilink": "http://en.wikipedia.org/Category:Transport",
        "id": 939
    },{
        "topic": "Low-carbon economy",
        "wikilink": "http://en.wikipedia.org/Category:Low-carbon_economy",
        "id": 1406
    },{
        "topic": "Vehicle technology",
        "wikilink": "http://en.wikipedia.org/Category:Vehicle_technology",
        "id": 1407
    },{
        "topic": "Wheeled vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Wheeled_vehicles",
        "id": 1408
    },{
        "topic": "Transportation engineering",
        "wikilink": "http://en.wikipedia.org/Category:Transportation_engineering",
        "id": 1273
    },{
        "topic": "Green vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Green_vehicles",
        "id": 1409
    },{
        "topic": "Electric power",
        "wikilink": "http://en.wikipedia.org/Category:Electric_power",
        "id": 1071
    },{
        "topic": "Land vehicles",
        "wikilink": "http://en.wikipedia.org/Category:Land_vehicles",
        "id": 1410
    }]

因此结果应如下所示：

[{
    "topic": "Automotive technologies",
    "wikilink": "http://en.wikipedia.org/Category:Automotive_technologies",
    "id": 1411,
    "count": 3
},{
    "topic": "Government incentives for plug-in electric vehicles",
    "wikilink": "http://en.wikipedia.org/Government_incentives_for_plug-in_electric_vehicles",
    "id": 1412,
    "count": 5
},{
    "topic": "Electric car",
    "wikilink": "http://en.wikipedia.org/Electric_car",
    "id": 932,
    "count": 3
},{
    "topic": "Electric vehicle manufacturers",
    "wikilink": "http://en.wikipedia.org/Category:Electric_vehicle_manufacturers",
    "id": 1413
},{
    "topic": "Cars",
    "wikilink": "http://en.wikipedia.org/Category:Cars_by_country",
    "id": 1414,
    "count": 2
}]

Answer 1

demo: db<>fiddle

在单独的子查询中将行分组：

SELECT  
    COALESCE(
        JSONB_AGG(
            JSONB_BUILD_OBJECT('id', v.id, 'topic', v.topic, 'wikilink', v.wikilink, 'count', v.count)
        ) FILTER (WHERE /*<your filter>*/),  -- A
        '[]'
    ) as TopicWords
FROM (
    SELECT 
        v.id, v.topic, v.wikilink,
        count(*)                             -- B
    FROM /*<your query>*/ v                  -- A
    GROUP BY v.id, v.topic, v.wikilink
) v

A：出于测试目的，我用您的数据制成了一个表格。实际上，这应该是一个更大的连接。与您使用FILTER模拟的true子句相同。当然，您仍然可以使用联接表和查询。

B：使用COUNT聚合。此值将添加为新列，可在您的JSONB_BUILD_OBJECT函数中使用。

Answer 2

您应该过滤，分组和计算派生表中的计数，例如：

select coalesce(jsonb_agg(to_jsonb(q)), '[]') as topicwords
from (
    select id, topic, wikilink, count(*)
    from your_query_without_select
    where topicwordid is not null
    group by 1, 2, 3
    ) q

获取jsonb_agg函数中特定ID的计数

2 个答案: