在JSONB列中查找與哈希數組中的列表不匹配的所有值

Question

可以說我有一個表，其中包含一個名為fields的JSONB列。 我的表tbl_1包含以下值，

ID   Fields
-------------------------------------------------------------
 1   [{"label": "Request For"}, {"label": "Requestor"}]
 2   [{"label": "Request For"}, {"label": "Meeting"}, {"label": "XYZ"}]
 3   [{"label": "Request For"}, {"label": "Meeting With"}, {"label": "ABC"}]

現在，我有了一個列表["ABC", "Request For", "ZZZ", "ABC"] 。 我想查找單個查詢中表中不存在上述列表中的哪個元素。 上面列表的預期輸出應為["ZZZ"]

Answer 1

where子句中not exists使用，例如：

with my_table(if, fields) as (
values
    (1, '[{"label": "Request For"}, {"label": "Requestor"}]'::jsonb),
    (2, '[{"label": "Request For"}, {"label": "Meeting"}, {"label": "XYZ"}]'),
    (3, '[{"label": "Request For"}, {"label": "Meeting With"}, {"label": "ABC"}]')
)

select item
from jsonb_array_elements('["ABC", "Request For", "ZZZ", "ABC"]') as item
where not exists (
    select 1
    from my_table
    cross join lateral jsonb_array_elements(fields)
    where value->'label' = item
    )

 item  
-------
 "ZZZ"
(1 row) 

---

@>運算符的替代解決方案，它給出了一個更簡單的執行計划：

select item
from jsonb_array_elements('["ABC", "Request For", "ZZZ", "ABC"]') as item
where not exists (
    select 1
    from my_table
    where fields @> jsonb_build_array(jsonb_build_object('label', item))
    )

您可以測試實際數據中哪個更快。

Answer 2

這也有效

SELECT 
    a.col
FROM
    tbl_1  t
    CROSS JOIN LATERAL
    jsonb_to_recordset(t.fields) as j("label" text)
    right join 
    (
        select unnest(ARRAY['ABC', 'Request For', 'ZZZ', 'ABC'])as col
    ) a
    on j."label" = a.col
where j."label" is null