Question

我正在使用PostgreSQL 10.6。我的表有一个jsonb列travel，其中填充了以下示例数据。下面是sqlfiddle;

我的桌子：

id | travel                                                                                                                                                                                                   
-: | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 1 | {"name": "Lucy", "trips": [{"city": "Tokyo", "continent": "Asia"}, {"city": "Bangkok", "continent": "Asia"}, {"city": "Paris", "continent": "Europe"}, {"city": "London", "continent": "Europe"}]}       
 2 | {"name": "Tom", "trips": [{"city": "Tokyo", "continent": "Asia"}, {"city": "Kyoto", "continent": "Asia"}, {"city": "Frankfurt", "continent": "Europe"}, {"city": "London", "continent": "Europe"}]}      
 3 | {"name": "Lenny", "trips": [{"city": "Tokyo", "continent": "Asia"}, {"city": "Bangkok", "continent": "Asia"}, {"city": "New York", "continent": "America"}, {"city": "Seattle", "continent": "America"}]}

DDL并插入代码：

create table people (
    id serial primary key,
    travel jsonb
);

insert into people (travel) values (
'{
    "name": "Lucy",
    "trips": [
      {
        "continent": "Asia",
        "city": "Tokyo"
      },
      {
        "continent": "Asia",
        "city": "Bangkok"
      },
      {
        "continent": "Europe",
        "city": "Paris"
      },
      {
        "continent": "Europe",
        "city": "London"
      }
    ]
  }
'::jsonb);

insert into people (travel) values (
'{
    "name": "Tom",
    "trips": [
      {
        "continent": "Asia",
        "city": "Tokyo"
      },
      {
        "continent": "Asia",
        "city": "Kyoto"
      },
      {
        "continent": "Europe",
        "city": "Frankfurt"
      },
      {
        "continent": "Europe",
        "city": "London"
      }
    ]
  }
'::jsonb);

insert into people (travel) values (
'{
    "name": "Lenny",
    "trips": [
      {
        "continent": "Asia",
        "city": "Tokyo"
      },
      {
        "continent": "Asia",
        "city": "Bangkok"
      },
      {
        "continent": "America",
        "city": "New York"
      },
      {
        "continent": "America",
        "city": "Seattle"
      }
    ]
  }
'::jsonb);

我如何查询在亚洲大陆上带有“ o” 字母的城市的旅行？

感谢与问候

Answer 1

我认为您自己的答案就可以了。数组选择可以稍微简化一些，大陆筛选条件的重复也很难看-我可能会写

SELECT *
FROM (
  SELECT
    travel -> 'name' as name,
    ARRAY(
      SELECT mytrips
      FROM jsonb_array_elements(travel -> 'trips') mytrips
      WHERE mytrips ->> 'continent' = 'Europe'
    ) as trips
  FROM
    people
  ) t
WHERE 
  trips <> '{}'

^{（online demo）}
另一方面，如果确实在travel上有索引，则@>子句中的WHERE运算符可能会更快。

可能更简单，但是对于同一个人的多次旅行而言，具有不同的语义是一种分组方法：

SELECT travel -> 'name' as name, jsonb_agg(trip) as trips
FROM people, jsonb_array_elements(travel -> 'trips') trip
WHERE trip ->> 'continent' = 'Europe'
GROUP BY name

^{（online demo）}

Answer 2

我不清楚您的预期输出是多少。但是要在o中找到Asia的城市就像这样：

demo:db<>fiddle

SELECT 
    * 
FROM 
    people,
    jsonb_array_elements(travel -> 'trips') elems
WHERE
    elems ->> 'city' LIKE '%o%'
    AND elems ->> 'continent' = 'Asia'

将数组元素分别扩展为一行
按continent和city过滤

Answer 3

我可以通过以下查询获得所需的结果。但是，我不确定在性能方面是否最佳。有任何建议使其性能更好吗？

SELECT
  travel -> 'name',   
   Array(      
      (SELECT elements.mytrips FROM
       (SELECT jsonb_array_elements(travel -> 'trips') as mytrips) as elements  
       WHERE elements.mytrips ->> 'continent' = 'Europe'
      )     
    )   
FROM 
  people
WHERE 
  travel -> 'trips' @> '[{"continent": "Europe"}]'

通过内部属性进行PostgreSQL jsonb查询

3 个答案: