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JSONB

Use the JSONB data type to create a column that can store JSON data.

Notes:

  • Numbers not representable by IEEE 754 double precision floating point may have poor interoperability, notably numbers in the bigint type larger than (2**53)-1.
  • Avoid using a JSONB column for GROUP BY and ORDER BY clauses or PRIMARY and INDEX keys. The exact behavior may change in the future.
    • The suggested usage is to extract the target field and cast to a simple type.
  • If you have JSON data contained in a string..
    • use STRUCT if the schema is known,
    • or use VARCHAR and convert it into JSONB later.

Define a JSONB type

Syntax: JSONB

Examples

The statement below creates a table x that contains a JSONB column named j_data.

CREATE TABLE x (j_data JSONB, d INTEGER);

The statement below creates a table y that contains a JSONB column named metadata.

CREATE TABLE y (id VARCHAR, metadata JSONB);

Below is a real world example.

CREATE TABLE product (
name VARCHAR,
price NUMERIC,
attributes JSONB
);

Add values to a JSONB column

To add values to a JSONB column, simply write the JSON as a string. For example, '{"key": "value"}'.

Examples

The statement below adds values to table x.

INSERT INTO x VALUES ('{"a": 3, "b": 4}', 5);

The statement below adds values to table y.

INSERT INTO y VALUES ('ABCD1234', '{"color": "blue", "size": "M"}');

The statement below adds values to table product.

INSERT INTO product (name, price, attributes)
VALUES
(
'T-Shirt',
19.99,
'{"color": "red", "size": "L"}'
);

Retrieve data from a JSONB column and casting

To retrieve data from a JSONB column, use the -> or ->> operators to access the JSON object's properties. The -> operator returns a jsonb value, while the ->> operator returns a varchar value.

For details about the JSON operators, see JSON operators.

JSONB data types can be cast to other data types such as bool, smallint, int, bigint, decimal, real, and double precision. Casting is performed using the ::data-type cast notation, such as ::int for casting to an integer data type.

Examples

Here are some examples for retrieving data and casting:

INSERT INTO product VALUES ('USB cable', 4.99, '{"lengthInFeet": 3, "backorder": true, "brand": "sin90", "compatible": ["pc", "mac", "phone"]}');

SELECT
(attributes -> 'lengthInFeet')::INT * 30.48 AS cm,
NOT (attributes -> 'backorder')::BOOL AS available,
UPPER(attributes ->> 'brand') AS brand_good,
UPPER((attributes -> 'brand')::VARCHAR) AS brand_bad,
attributes -> 'compatible'
FROM product;

-----Result

cm | available | brand_good | brand_bad | ?column?
-------+-----------+------------+-----------+------------------------
91.44 | f | SIN90 | "SIN90" | ["pc", "mac", "phone"]
(1 row)

The output shows that the brand_bad column contains additional double quotes. So when the target column is a varchar, stick to the dedicated operator ->> directly rather than using the cast. Only cast a boolean or a number.

JSONB functions and operators

For the full list of JSON and JSONB functions and operators, see JSON functions and operators.

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