******************************* JSON Functions ******************************* .. function:: json_extract_path_text (json text, json_path text) Extracts JSON string from a JSON string based on json path specified and returns JSON string pointed to by JSONPath. Returns null if either argument is null. :param json: JSON string :param json_path: JSONpath :rtype: text :example: .. code-block:: sql select json_extract_path_text('{"test" : {"key" : "tajo"}}','$.test.key'); > tajo .. function:: json_array_get (json_array text, index int4) Returns the element at the specified index into the JSON array. This function returns an element indexed from the end of an array with a negative index, and null if the element at the specified index doesn’t exist. :param json_array: String of a JSON array :param index: index :rtype: text :example: .. code-block:: sql select json_array_get('[100, 200, 300]', 0); > 100 select json_array_get('[100, 200, 300]', -2); > 200 .. function:: json_array_contains (json_array text, value any) Determine if the given value exists in the JSON array. :param json_array: String of a JSON array :param value: value of any type :rtype: text :example: .. code-block:: sql select json_array_contains('[100, 200, 300]', 100); > t .. function:: json_array_length(json_array text) Returns the length of json array. :param json_array: String of a JSON array :rtype: int8 :example: .. code-block:: sql select json_array_length('[100, 200, 300]'); > 3