Sql 向Json数组添加新元素

我想在下面的位置向a3添加一个新的数组元素：

{
    "a1": "e1",
    "a2": {
        "b1": "y1",
        "b2": "y2"
    },
    "a3": [{
            "arr1": "1"
        },
        {
            "arr2": "2"
        }
    ]
}

所以我希望上面的json是这样的：

{
    "a1": "e1",
    "a2": {
        "b1": "y1",
        "b2": "y2"
    },
    "a3": [{
            "arr1": "1"
        },
        {
            "arr2": "2"
        },
        {
            "arr3": "3"
        }
    ]
}

我可以用下面的命令添加新元素。但当涉及到数组时，我找不到添加新元素的方法

SELECT jsonb_set('{ "a1": "e1", "a2": { "b1": "y1", "b2": "y2" }, "a3": [{ "arr1": "1" }, { "arr2": "2" }] }'::jsonb,
'{a2,b3}', 
'"4"');

我应该使用什么命令将{“arr3”：“3”}添加到a3

---

编辑：如果arr3已存在，则命令应更改其值。不应向数组添加重复的{“arr3”：“3”}。

使用串联运算符

|

：

with my_data(json_data) as (
values
    ('{ "a1": "e1", "a2": { "b1": "y1", "b2": "y2" }, "a3": [{ "arr1": "1" }, { "arr2": "2" }] }'::jsonb)
)

select jsonb_set(json_data, '{a3}', json_data->'a3' || '{"arr3": "3"}')
from my_data;

                                             jsonb_set                                             
---------------------------------------------------------------------------------------------------
 {"a1": "e1", "a2": {"b1": "y1", "b2": "y2"}, "a3": [{"arr1": "1"}, {"arr2": "2"}, {"arr3": "3"}]}
(1 row)

检查嵌套数组中是否存在密钥有点复杂。您应该使用

jsonb\u array\u elements（）

卸载数组，以执行以下操作：

with my_data(json_data) as (
values
    ('{ "a1": "e1", "a2": { "b1": "y1", "b2": "y2" }, "a3": [{ "arr1": "1" }, { "arr2": "2" }] }'::jsonb)
)

select 
    case when already_exists then json_data
    else jsonb_set(json_data, '{a3}', json_data->'a3' || '{"arr3": "3"}')
    end as json_data
from (
    select json_data, bool_or(value ? 'arr3') as already_exists
    from my_data
    cross join jsonb_array_elements(json_data->'a3')
    group by 1
    ) s

如果存在{“arr3”：“3”}，该命令将添加新的{“arr3”：“3”}。如果arr3密钥已经存在，有没有办法让它更改arr3值，或者什么都不做？