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PostgreSQL jsonb_typeof() Function

Summary: in this tutorial, you will learn how to use the PostgreSQL jsonb_typeof() function to return the type of the top-level JSON value as a text string.

Introduction to the PostgreSQL jsonb_typeof() function​

The jsonb_typeof() function allows you to get the type of a top-level JSONB value as a text string.

Here’s the syntax of the jsonb_typeof() function:

jsonb_typeof(jsonb_value)

In this syntax:

  • jsonb_value is a JSONB value of which you want to get the type as a text string.

The jsonb_typeof() function returns a text string representing the type of the input JSONB value. The possible return values are object, array, string, number, and null.

PostgreSQL jsonb_typeof() function examples​

Let’s take some examples of using the jsonb_typeof() function.

The following example uses the jsonb_typeof() function to return the type of a JSON object:

SELECT jsonb_typeof('{}');

Output:

 jsonb_typeof
--------------
 object
(1 row)

The following example uses the jsonb_typeof() function to return the type of a JSON array:

select jsonb_typeof('[]');

Output:

 jsonb_typeof
--------------
 array
(1 row)

The following example uses the jsonb_typeof() function to return the type of a number:

SELECT jsonb_typeof('1'::jsonb);

Output:

 jsonb_typeof
--------------
 number
(1 row)

The following example uses the jsonb_typeof() function to return the type of null:

SELECT jsonb_typeof('null'::jsonb);

Output:

 jsonb_typeof
--------------
 null
(1 row)

The following example uses the jsonb_typeof() function to return the type of string:

SELECT
  jsonb_typeof(
    jsonb_path_query('{"name": "Alice"}', '$.name')
  );

Output:

 jsonb_typeof
--------------
 string
(1 row)

Summary​

  • Use the jsonb_typeof() function to return the type of the top-level JSON value as a text string.