Return results of a sql query as JSON in oracle 12c

Question

Background

I need to fetch a few thousands rows from Oracle and convert them to JSON for use in SlickGrid. Currently I am fetching the rows in PHP,

Answer 1

You can use the xmltype to convert the result of an SQL into XML and JSON. See the following article for the solution which will work for Oracle since version 9. You can also download the package itstar_xml_util:

http://stefan-armbruster.com/index.php/12-it/pl-sql/12-oracle-xml-and-json-goodies

A simple example with the emp table:

declare
  l_sql_string varchar2(2000);
  l_xml        xmltype;
  l_json       xmltype;
begin
  l_sql_string := 'select a.empno, a.ename, a.job from emp a';

  -- Create the XML from SQL
  l_xml := itstar_xml_util.sql2xml(l_sql_string);

  -- Display the XML
  dbms_output.put_line(l_xml.getclobval());

  l_json := itstar_xml_util.xml2json(l_xml);
  -- Display the JSON
  dbms_output.put_line(l_json.getclobval());  
end;

The result looks like this:

{"ROWSET": [
    {
      "EMPNO": 7839,
      "ENAME": "KING",
      "JOB": "PRESIDENT"
    },
    {
      "EMPNO": 7698,
      "ENAME": "BLAKE",
      "JOB": "MANAGER"
    },
[...]
    {
      "EMPNO": 7934,
      "ENAME": "MILLER",
      "JOB": "CLERK"
    }
  ]}