Sorting the result set return by EXTRACT for XMLTYPE

Question

What is the best way to order the output return by extract?
    My SELECT statement:
     SELECT
            regexp_replace(regexp_replace(extract(xmltype(t.message_xml), '//Event'),'<Event>',''),'</Event>',',')
            FROM SUB_XML T
            Current output: EVT_B3_TRAN,EVT_B3_PROD,EVT_B3_FX,EVT_B3_ACC,EVT_B3_PRICE
            Required output: EVT_B3_ACC,EVT_B3_FX,EVT_B3_PROD,EVT_B3_PRICE, EVT_B3_TRAN

Answer 1

Please post your example data so that people can help you.
You would be better to extract the contents of the XML using the XMLTABLE functionality, rather than an extract with regexp_replace string functions.  Treat the XML as XML, not as strings.
Example:
SQL> ed
Wrote file afiedt.buf
  1  with t as (select xmltype('<XML>
  2    <Event>EVT_B3_TRAN</Event>
  3    <Event>EVT_B3_PROD</Event>
  4    <Event>EVT_B3_FX</Event>
  5    <Event>EVT_B3_ACC</Event>
  6    <Event>EVT_B3_PRICE</Event>
  7  </XML>') as xml from dual)
  8  --
  9  -- end of example XML
10  --
11  select listagg(event,',') within group (order by rn) as events
12  from (
13        select x.event
14              ,row_number() over (order by x.event) as rn
15        from   t
16              ,xmltable('/XML/Event'
17                        passing t.xml
18                        columns event varchar2(20) path '.'
19                       ) x
20*      )
SQL> /
EVENTS
EVT_B3_ACC,EVT_B3_FX,EVT_B3_PRICE,EVT_B3_PROD,EVT_B3_TRAN