XML QUERY LOGIC

Question

I have example xml as following :
with table1 AS
(select xmltype(
'<Organization>'||
'  <Employee>'||
'    <EmployeeIdentification>'||
'      <Identifier>33649613</Identifier>'||
'      <ProgramCD>ACCOUNTING</ProgramCD>'||
'    </EmployeeIdentification>'||
'    <EmployeeIdentification>'||
'      <Identifier>000007</Identifier>'||
'      <ProgramCD>PEOPLESOFT</ProgramCD>'||
'    </EmployeeIdentification>'||
'  </Employee>'||
'  <Employee>'||
'    <EmployeeIdentification>'||
'      <Identifier>33649614</Identifier>'||
'      <ProgramCD>ACCOUNTING</ProgramCD>'||
'    </EmployeeIdentification>'||
'    <EmployeeIdentification>'||
'      <Identifier>000008</Identifier>'||
'      <ProgramCD>PEOPLESOFT</ProgramCD>'||
'    </EmployeeIdentification>'||
'  </Employee>'||
'</Organization>'
) xmlcol from dual
select ExtractValue(column_Value, '/EmployeeIdentification/Identifier') Identifier
     , ExtractValue(column_Value, '/EmployeeIdentification/ProgramCD') ProgramCD
  from table1 t1
     , table(XMLSequence(extract(t1.xmlcol,'/Organization/Employee/EmployeeIdentification'))) v;I got this output :
IDENTIFIER      PROGRAMCD      
33649613        ACCOUNTING     
000007          PEOPLESOFT     
33649614        ACCOUNTING     
000008          PEOPLESOFT There is no attributes in <Employee>. Is there a way to get below output?
ACCOUNTING_ID  PEOPLESOFT_ID
33649613       000007
33649614       000008

Answer 1

If the number of columns you want is dynamic, I think the only way is using [pipelined table functions|http://www.oracle.com/pls/db102/print_hit_summary?search_string=pipelined+table+functions].
If the number of columns, e.g. the number of distinct ProgramCDs, is fixed (two in this example) you can use a PIVOT query (Oracle 11gR1 and above):
SQL> with table1 AS
  2  (select xmltype(
  3  '<Organization>'||
  4  '  <Employee>'||
  5  '    <EmployeeIdentification>'||
  6  '      <Identifier>33649613</Identifier>'||
  7  '      <ProgramCD>ACCOUNTING</ProgramCD>'||
  8  '    </EmployeeIdentification>'||
  9  '    <EmployeeIdentification>'||
10  '      <Identifier>000007</Identifier>'||
11  '      <ProgramCD>PEOPLESOFT</ProgramCD>'||
12  '    </EmployeeIdentification>'||
13  '  </Employee>'||
14  '  <Employee>'||
15  '    <EmployeeIdentification>'||
16  '      <Identifier>33649614</Identifier>'||
17  '      <ProgramCD>ACCOUNTING</ProgramCD>'||
18  '    </EmployeeIdentification>'||
19  '    <EmployeeIdentification>'||
20  '      <Identifier>000008</Identifier>'||
21  '      <ProgramCD>PEOPLESOFT</ProgramCD>'||
22  '    </EmployeeIdentification>'||
23  '  </Employee>'||
24  '</Organization>'
25  ) xmlcol from dual
26  )
27  select accounting_id, peoplesoft_id from (
28  select ExtractValue(v.column_Value, '/EmployeeIdentification/Identifier') Identifier
29       , ExtractValue(v.column_Value, '/EmployeeIdentification/ProgramCD') ProgramCD
30       , Extract(e.column_Value, '.').getStringVal() emp
31    from table1 t1
32       , table(XMLSequence(extract(t1.xmlcol,'/Organization/Employee/EmployeeIdentification'))) v
33       , table(XMLSequence(extract(t1.xmlcol,'/Organization/Employee'))) e
34   where instr(Extract(e.column_Value, '/Employee/EmployeeIdentification/Identifier').getStringVal(),
35         ExtractValue(v.column_Value, '/EmployeeIdentification/Identifier'))>0
36  ) pivot (min(Identifier) for ProgramCD in ('ACCOUNTING' as accounting_id, 'PEOPLESOFT' as peoplesoft_id));
ACCOUNTING_ID                  PEOPLESOFT_ID
33649614                       000008
33649613                       000007Max
[My Italian Oracle blog|http://oracleitalia.wordpress.com/2010/01/07/creare-documenti-office-da-plsql/]