Oracle 23c

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select * from V$VERSION;


BANNER
BANNER_FULL
BANNER_LEGACY
CON_ID


Oracle Database 23c Free, Release 23.0.0.0.0 - Developer-Release
Oracle Database 23c Free, Release 23.0.0.0.0 - Developer-Release
Version 23.2.0.0.0
Oracle Database 23c Free, Release 23.0.0.0.0 - Developer-Release
0


CREATE TABLE sometable(instance_number) AS
SELECT LEVEL FROM DUAL CONNECT BY LEVEL <= 3;
3 rows affected

Declare
  p_clob CLOB;
begin
  SELECT JSON_ARRAYAGG(
           JSON_OBJECT(
             KEY 'AttachedDocumentId'          VALUE TO_CHAR(SYSTIMESTAMP,'mmddyyyyhhmiss'),
             KEY 'DatatypeCode'                VALUE 'TEXT',
             KEY 'CategoryName'                VALUE 'INSTANCE_NUMBER',
             KEY 'UploadedText'                VALUE instance_number,
             KEY 'UploadedFileContentType'     VALUE 'text',
             KEY 'ContentRepositoryFileShared' VALUE 'false',
             KEY 'Title'                       VALUE instance_number,
             KEY 'Description'                 VALUE instance_number
           )
           RETURNING CLOB
         )
  INTO   p_clob
  FROM   sometable;

  DBMS_OUTPUT.PUT_LINE(p_clob);
END;
/
1 rows affected

dbms_output:
[{"AttachedDocumentId":"09042023125230","DatatypeCode":"TEXT","CategoryName":"INSTANCE_NUMBER","UploadedText":1,"UploadedFileContentType":"text","ContentRepositoryFileShared":"false","Title":1,"Description":1},{"AttachedDocumentId":"09042023125230","DatatypeCode":"TEXT","CategoryName":"INSTANCE_NUMBER","UploadedText":2,"UploadedFileContentType":"text","ContentRepositoryFileShared":"false","Title":2,"Description":2},{"AttachedDocumentId":"09042023125230","DatatypeCode":"TEXT","CategoryName":"INSTANCE_NUMBER","UploadedText":3,"UploadedFileContentType":"text","ContentRepositoryFileShared":"false","Title":3,"Description":3}]