postgres 中有(v 9.5,如果重要的话):
create table json_test(
id varchar NOT NULL,
data jsonb NOT NULL,
PRIMARY KEY(id)
);
其中数据是json,包含数组的数组
{
"attribute": "0",
"array1": [{
"id": "a12",
"attribute": "1",
"array2": [{
"id": "a21",
"attribute": "21"
}]
},
{
"id": "a12",
"attribute": "2",
"array2": [{
"id": "22",
"attribute": "22"
}]
}]
}
必需:
select id from json_test where
json_test->>'attribute'='0' and
array1.[id='a12'].array2.attribute='22'
查询的意思应该是:给我所有的id
- 一些顶级属性有特定的值
- 数组中的特定对象具有必需的属性
- 某些对象(来自 array2)特别是 array1 具有必需的属性
诀窍在于如何实现最后一个条件。
另一个例子:
{
"attribute": "0",
"array1": [{
"id": "a12",
"attribute": "1",
"array2": [{
"id": "a21_1",
"attribute_1": "21_1"
},{
"id": "a21_2",
"attribute_2": "21_2"
}]
}]
}
select * from json_test where
array1.[id='a12'].array2.attribute_1='21_1' and
array1.[id='a12'].array2.attribute_2='21_2'
最佳答案
检索嵌套 json 数组的最通用方法是使用多个 jsonb_array_elements()
在横向连接。示例:
with json_test(id, data) as (
values
(1,
'{
"attribute": "0",
"array1": [{
"id": "a12",
"attribute": "1",
"array2": [{
"id": "a21",
"attribute": "21"
}]
},
{
"id": "a12",
"attribute": "2",
"array2": [{
"id": "22",
"attribute": "22"
}]
}]
}'::jsonb)
)
select id, elem2
from
json_test,
jsonb_array_elements(data->'array1') array1(elem1),
jsonb_array_elements(elem1->'array2') array2(elem2)
where elem2->>'id' = '22';
id | elem2
----+---------------------------------
1 | {"id": "22", "attribute": "22"}
(1 row)
该方法是通用的,因为您可以轻松访问任何级别的任何 json 对象的任何值,例如:
...
where
data->>'attribute' = '0'
and elem1->>'id' = 'a12'
and elem2->>'id' = 'a21_1';
关于arrays - Postgres JSONB : where clause for arrays of arrays,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/38201823/