Hi,
I want to parse xml like:

<xml>
<field1>value1</field1>
<field2>value2</field2>
<field3>value3</field3>
</xml>

I write query, using xmltable and unpivot:

select *
  from (select p.field1,
               p.field2,
               p.field3
          from (select xmltype('<xml><field1>value1</field1><field2>value2</field2><field3>value3</field3></xml>') as xml
                  from dual) t,
               xmltable('/xml' passing t.xml columns 
                        field1 varchar2(100) path 'field1',
                        field2 varchar2(100) path 'field2',
                        field3 varchar2(100) path 'field3'
               ) p
         )
unpivot (value for field in (field1, field2, field3))

I expect to receive 3 rows, but returns only 1, why?
Is works correctly, if I add "union all" and "select from dual where 1=2" like:

select *
  from (select p.field1,
               p.field2,
               p.field3
          from (select xmltype('<xml><field1>value1</field1><field2>value2</field2><field3>value3</field3></xml>') as xml
                  from dual) t,
                       xmltable('/xml' passing t.xml columns 
                       field1 varchar2(100) path 'field1',
                       field2 varchar2(100) path 'field2',
                       field3 varchar2(100) path 'field3'
                ) p
                union all
                select '1' as column1,
                       '1' as column2,
                       '1' as column3
                  from dual where 1=2
        )
unpivot (value for field in (field1, field2, field3))

What to do? This is a bug?
I want to write code without unnecessary constructions