PostgreSQL: Remove attribute from JSON column

Question

I need to remove some attributes from a json type column.

The Table:

CREATE TABLE my_table( id VARCHAR(80), data json);
INSERT INTO my_table (id, dat         


        

Answer 1

While this is certainly easier in 9.5+ using the jsonb operators, the function that pozs wrote to remove multiple keys is still useful. For example, if the keys to be removed are stored in a table, you could use the function to remove them all. Here is an updated function, using jsonb and postgresql 9.5+:

CREATE FUNCTION remove_multiple_keys(IN object jsonb, 
                                     variadic keys_to_delete text[], 
                                     OUT jsonb)
  IMMUTABLE
  STRICT
  LANGUAGE SQL
AS 
$$
  SELECT jsonb_object_agg(key, value)
     FROM (SELECT key, value 
           FROM jsonb_each("object")
           WHERE NOT (key = ANY("keys_to_delete")) 
     ) each_subselect
$$
;

If the keys to be removed are stored in a table, (e.g. in the column "keys" of the table "table_with_keys") you could call this function like this:

SELECT remove_multiple_keys(my_json_object, 
                            VARIADIC (SELECT array_agg(keys) FROM table_with_keys));

Answer 2

Simply use the #- operator, for example:

SELECT '{"foo": 10, "bar": [], "baz": {}}'::jsonb #- '{baz}';