In postgresql, how can I return a boolean value instead of string on a jsonb key?

Question

In the query below, $isComplete and $isValid are returned as a string. However, they are saved as boolean values. How can I get the boolean representation of these fields to be returned?

query =
    "SELECT
        data #>> '{id}' AS id,
        data #>> '{name}' AS name,
        data #>> '{curator}' AS curator,
        data #>  '{$isValid}' as \"$isValid\",
        data #>  '{customer}' as customer,
        data #>  '{$createdTS}' as \"$createdTS\",
        data #>  '{$updatedTS}' as \"$updatedTS\",
        data #>  '{$isComplete}' as \"$isComplete\",
        (count(keys))::numeric as \"numProducts\"
    FROM
      appointment_intakes,
      LATERAL jsonb_object_keys(data #> '{products}') keys
    GROUP BY id"

Solution

Simply cast a text to boolean:

create table jsonb_test (id int, data jsonb);
insert into jsonb_test values
(1, '{"is_boolean" : true}'),
(2, '{"is_boolean" : false}');

select id, data, (data->>'is_boolean')::boolean as is_boolean
from jsonb_test
where (data->>'is_boolean')::boolean

 id |          data          | is_boolean 
----+------------------------+------------
  1 | {"is_boolean": true}   | t
(1 row)

Note that you can also cast other json text values to boolean, examples:

insert into jsonb_test values
(3, '{"is_boolean" : "true"}'),
(4, '{"is_boolean" : "false"}'),
(5, '{"is_boolean" : "t"}'),
(6, '{"is_boolean" : "f"}'),
(7, '{"is_boolean" : "on"}'),
(8, '{"is_boolean" : "off"}');

select id, data, (data->>'is_boolean')::boolean as is_boolean
from jsonb_test
where (data->>'is_boolean')::boolean

 id |          data          | is_boolean 
----+------------------------+------------
  1 | {"is_boolean": true}   | t
  3 | {"is_boolean": "true"} | t
  5 | {"is_boolean": "t"}    | t
  7 | {"is_boolean": "on"}   | t
(4 rows)

Read about valid literals for boolean type in the documentation.

---

Update

Postgres 11 adds casts from JSONB scalars to numeric and boolean data types. This query will work only for regular boolean JSONB scalars (i.e. true or false):

select id, data, (data->'is_boolean')::boolean as is_boolean
from jsonb_test
where (data->'is_boolean')::boolean