[英]postgresql jsonb query by inner property
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;
http://sqlfiddle.com/#!17/e52ff/1
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 和插入代码:
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);
如何查询到亚洲大陆有“o”字母的城市的旅行?
感谢和问候
我认为您自己的答案很好。 数组选择可以简化一点,大陆过滤条件的重复有点难看——我大概会写
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 <> '{}'
( 在线演示)
另一方面,如果您在travel
上有索引,则WHERE
子句中的@>
运算符可能会更快。
可能更简单,但对于同一个人的多次旅行具有不同的语义,将是一种分组方法:
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
( 在线演示)
我不太清楚您期望的 output 是什么。 但是要在Asia
找到带有o
的城市是这样的:
SELECT
*
FROM
people,
jsonb_array_elements(travel -> 'trips') elems
WHERE
elems ->> 'city' LIKE '%o%'
AND elems ->> 'continent' = 'Asia'
continent
和city
过滤我可以通过以下查询获得我想要的结果。 但是,我不确定它是否在性能方面是最佳的。 有什么建议可以让它表现得更好吗?
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"}]'
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