postgresql - 从对象 JSONB 中的数组中删除元素

Question

我正试图从我的数据库中删除一个元素。我要删除的元素位于一个名为 playerContainer 的 JSON 对象中，该对象包含一个名为 players 的数组。这一切都位于一个名为 site_content 的表中。我试图根据对象的 ID 删除该对象，但出现此错误。

DELETE elem from site_content, lateral jsonb_array_elements(content->'playersContainer'->'players') elem where elem @> '{"id":"22"}'
because: ERROR: syntax error at or near "elem" Position: 27

下面是我的查询，谁能看出我哪里出错了？

DELETE elem 
from site_content, 
lateral jsonb_array_elements(content->'playersContainer'->'players') elem 
where elem @> '{"id":"1"}' 

这是示例 JSON

"playersContainer": {
        "players": [
            {
                "id": "1",
                "name": "Nick",
                "teamName": "Shire Soldiers",
                "ratings": [
                    1,
                    5,
                    6,
                    9
                ],
                "assists": 17,
                "manOfTheMatches": 20,
                "cleanSheets": 1,
                "data": [
                    3,
                    2,
                    3,
                    5,
                    6
                ],
                "totalGoals": 19

            },
}

Answer 1

DELETE适用于表格的行。因此，除非您想删除整行，否则不能使用它。

试试这个:

create temp table testing as
select 
    '{ "playersContainer": {
        "players": [
            {
                "id": "1",
                "name": "Nick"
            },
            {
                "id": "2",
                "name": "Rick"
            },
            {
                "id": "3",
                "name": "Trick"
            }
        ]
     }}'::jsonb as value;

现在您需要找到要移除的玩家的位置，假设您想要 ID 为 2 的 Rick(负 1，因为索引从 0 开始)

select position-1 from testing, jsonb_array_elements(value->'playersContainer'->'players') with ordinality arr(elem, position) WHERE elem->>'id' = '2';

现在您可以将其与 UPDATE 语句结合使用来更新字段。使用减号 (-) 运算符删除所需索引处的元素。

UPDATE testing SET value = jsonb_set(value, '{playersContainer,players}', (value->'playersContainer'->'players') - (select position-1 from testing, jsonb_array_elements(value->'playersContainer'->'players') with ordinality arr(elem, position) WHERE elem->>'id' = '2')::int );

最终结果:

{
    "playersContainer":{
        "players":[
            {
                "id":"1",
                "name":"Nick"
            },
            {
                "id":"3",
                "name":"Trick"
            }
        ]
    }
}