postgresql,从json数组中检索特定键的值

with my_table(data) as (
values
('[
  {
    "skillId": "1",
    "skillLevel": 42
  },
  {
    "skillId": "2",
    "skillLevel": 41
  }
]'::jsonb)
)

select elem->>'skillLevel' as skill_level
from my_table
cross join jsonb_array_elements(data) elem
where elem->>'skillId' = '1';

 skill_level 
-------------
 42
(1 row) 

以上是最简单的方法,您可以在函数中使用该思想,例如:

create or replace function extract_skill_level(data jsonb, id int)
returns integer language sql as $$
    select (elem->>'skillLevel')::int
    from jsonb_array_elements(data) elem
    where elem->>'skillId' = id::text
$$;

select extract_skill_level
    ('[
      {
        "skillId": "1",
        "skillLevel": 42
      },
      {
        "skillId": "2",
        "skillLevel": 41
      }
    ]', 1);