Find position of object in postgres jsonb array

问题

I have an array of objects that looks like this within the jsonb value column of a table:

"west": [
  {"id": "aa92f346-7a93-4443-949b-4eab0badd983", "version": 1},
  {"id": "cd92e346-6b04-3456-050a-5eeb0bddd027", "version": 3}
]

I'm aiming to remove certain objects from this array based on their id and version like so:

SELECT value::jsonb #- '{west, 1}' FROM game.settings;

However, the 1 should not be hard-coded, but rather should equal the position of the object within the array which matches the id and version I'm looking for (in this case "id": "cd92e346-6b04-3456-050a-5eeb0bddd027", "version": 3).

How would I go about determining this array position and passing it into the spot my hard-coded 1 currently holds?

回答1:

Example data:

create temp table settings as
select 
    '{"west": [
      {"id": "aa92f346-7a93-4443-949b-4eab0badd983", "version": 1},
      {"id": "cd92e346-6b04-3456-050a-5eeb0bddd027", "version": 3}
    ]}'::jsonb as value;

You can use jsonb_array_elements() with ordinality to determine the array position of a given element:

select elem, position
from settings, jsonb_array_elements(value->'west') with ordinality arr(elem, position)
where elem->>'id' = 'cd92e346-6b04-3456-050a-5eeb0bddd027';

                             elem                             | position 
--------------------------------------------------------------+----------
 {"id": "cd92e346-6b04-3456-050a-5eeb0bddd027", "version": 3} |        2
(1 row)

Use position to remove the object from the array:

select value #- array['west', (position- 1)::text] new_value
from settings, jsonb_array_elements(value->'west') with ordinality arr(elem, position)
where elem->>'id' = 'cd92e346-6b04-3456-050a-5eeb0bddd027';

                                new_value                                 
--------------------------------------------------------------------------
 {"west": [{"id": "aa92f346-7a93-4443-949b-4eab0badd983", "version": 1}]}
(1 row)

来源：https://stackoverflow.com/questions/38640168/find-position-of-object-in-postgres-jsonb-array

标签

node.js

postgresql

jsonb