从 jsonb 数组中删除元素

Question

我有以下 jsonb。我想从数组页面中删除名为 'pageb' 的元素。类似问题中提供的解决方案对我不起作用。

'{
  "data": {
    "id": "a1aldjfg3f",
    "pages": [
      {
        "type": "pagea"
      },
      {
        "type": "pageb"
      }                                
    ],
    "activity": "test"
  }
}'

我的脚本现在看起来像这样。它没有 return 任何错误，但元素不会被删除。

  UPDATE database
  SET reports = jsonb_set(reports, '{data,pages}', (reports->'data'->'pages') - ('{"type":"pageb"}'), true)
  WHERE reports->'data'->'pages'  @> '[{"type":"pageb"}]';

Answer 1

以下是 for deleting an element inside an array reliably and the PostgreSQL's ability to use data-modifying WITH statements 的组合，但由于必要的相关性，它需要一个标识列（我的 test table 中的 id）才能工作：

WITH new_reports AS (
    SELECT
        id,
        reports #- array['data','pages',(position - 1)::text] AS new_value
    FROM
        test,
        jsonb_array_elements(reports->'data'->'pages') WITH ORDINALITY arr(item, position)
    WHERE
        test.reports->'data'->'pages' @> '[{"type":"pageb"}]'
        AND
        item->>'type' = 'pageb'
    )
UPDATE test SET reports = new_reports.new_value FROM new_reports WHERE test.id = new_reports.id;

我使用的测试数据：

SELECT reports FROM test;
                                               reports                                               
-----------------------------------------------------------------------------------------------------
 {"data": {"id": "a1aldjfg3f", "pages": [{"type": "pagea"}, {"type": "pagec"}], "activity": "test"}}
 {"data": {"id": "a1aldjfg3f", "pages": [{"type": "pagea"}, {"type": "pageb"}], "activity": "test"}}
 {"data": {"id": "a1aldjfg3f", "pages": [{"type": "pageb"}, {"type": "pagec"}], "activity": "test"}}
(3 rows)

...并在执行查询后：

SELECT reports FROM test;
                                               reports                                               
-----------------------------------------------------------------------------------------------------
 {"data": {"id": "a1aldjfg3f", "pages": [{"type": "pagea"}, {"type": "pagec"}], "activity": "test"}}
 {"data": {"id": "a1aldjfg3f", "pages": [{"type": "pagea"}], "activity": "test"}}
 {"data": {"id": "a1aldjfg3f", "pages": [{"type": "pagec"}], "activity": "test"}}
(3 rows)

希望对你有用。

Answer 2

这里不能应用-运算符，因为右边的操作数是定义键的字符串，per the documentation:

Delete key/value pair or string element from left operand. Key/value pairs are matched based on their key value.

从 json 数组中删除 json 对象可以通过解包数组并找到对象的索引来完成。使用此方法的查询可能过于复杂，因此在这种情况下定义自定义函数非常方便。

create or replace function jsonb_remove_array_element(arr jsonb, element jsonb)
returns jsonb language sql immutable as $$
    select arr- (
        select ordinality- 1
        from jsonb_array_elements(arr) with ordinality
        where value = element)::int
$$;

以及更新：

update my_table
set reports = 
    jsonb_set(
        reports, 
        '{data,pages}', 
        jsonb_remove_array_element(reports->'data'->'pages', '{"type":"pageb"}')
        )
where reports->'data'->'pages'  @> '[{"type":"pageb"}]';

Working example in rextester.

Answer 3

好了

do $$
declare newvar jsonb;
begin
    newvar := jsonb '{ "customer": "John Doe", "buy": [{"product": "Beer","qty": 6},{"product": "coca","qty": 5}]}';
    newvar := jsonb_set(newvar,'{buy}', jsonb_remove((newvar->>'buy')::jsonb,'{"product": "Beer"}'));
    newvar := jsonb_set(newvar,'{buy}', jsonb_add((newvar->>'buy')::jsonb,'{"product": "cofe","qty": 6}'));
    RAISE NOTICE '%', newvar; 
end $$

create or replace function jsonb_remove(arr jsonb, element jsonb)
returns jsonb language sql immutable as $$
    select ('['||coalesce(string_agg(r::text,','),'')||']')::jsonb from jsonb_array_elements(arr) r where r @> element=false
$$;

create or replace function jsonb_add(arr jsonb, element jsonb)
returns jsonb language sql immutable as $$
    select arr||element
$$;

从 jsonb 数组中删除元素

Remove element from jsonb array

arrays

postgresql

jsonb