1. SQL Language Reference
  2. Functions
  3. JSON_ARRAY

JSON_ARRAY

Syntax

Description of json_array.eps follows
Description of the illustration json_array.eps

JSON_on_null_clause::=

Description of json_on_null_clause.eps follows
Description of the illustration json_on_null_clause.eps

JSON_returning_clause::=

Description of json_returning_clause.eps follows
Description of the illustration json_returning_clause.eps

Purpose

The SQL/JSON function JSON_ARRAY takes as its input one or more SQL expressions, converts each expression to a JSON value, and returns a JSON array that contains those JSON values.

expr

For expr, you can specify any SQL expression that evaluates to a JSON object, a JSON array, a numeric literal, a text literal, date, timestamp, or null. This function converts a numeric literal to a JSON number value, and a text literal to a JSON string value. The date and timestamp data types are printed in the generated JSON object or array as JSON Strings following the ISO 8601 date format.

FORMAT JSON

Use this optional clause to indicate that the input string is JSON, and will therefore not be quoted in the output.

JSON_on_null_clause

Use this clause to specify the behavior of this function when expr evaluates to null.

  • NULL ON NULL - If you specify this clause, then the function returns the JSON null value.

  • ABSENT ON NULL - If you specify this clause, then the function omits the value from the JSON array. This is the default.

JSON_returning_clause

Use this clause to specify the type of return value. One of :

  • VARCHAR2 specifying the size as a number of bytes or characters. The default is bytes. If you omit this clause, or specify the clause without specifying the size value, then JSON_ARRAY returns a character string of type VARCHAR2(4000). Refer to VARCHAR2 Data Type for more information. Note that when specifying the VARCHAR2 data type elsewhere in SQL, you are required to specify a size. However, in the JSON_returning_clause you can omit the size.

  • CLOB to return a character large object containing single-byte or multi-byte characters.

  • BLOB to return a binary large object of the AL32UTF8 character set.

STRICT

Specify the STRICT clause to verify that the output of the JSON generation function is correct JSON. If the check fails, a syntax error is raised.

Refer to JSON_OBJECT for examples.

WITH UNIQUE KEYS

Specify WITH UNIQUE KEYS to guarantee that generated JSON objects have unique keys.

Examples

The following example constructs a JSON array from a JSON object, a JSON array, a numeric literal, a text literal, and null:

SELECT JSON_ARRAY (     
    JSON_OBJECT('percentage' VALUE .50),
    JSON_ARRAY(1,2,3),
    100,
    'California',
    null
    NULL ON NULL
    ) "JSON Array Example"
  FROM DUAL;
 
JSON Array Example
--------------------------------------------------------------------------------
[{"percentage":0.5},[1,2,3],100,"California",null]