Function returning SQL - dynamically select the column

Question

Hi there,
[Oracle 11g],
Hi there,
I want to dynamically select the column to be displayed.
Or lets say it in an easier way regarding the EMP Table:
I got a table called teststable with value1 and value2 in it.
Value1 is EMPNO
Value 2 is DEPTNO
Now I like to have something like this:
Select (Select Value1 from testtable),(Select Value2 from testtable) from EMP This will not work. So I need a function for this. Does someone now how to get this to work? Thx in advance. Thorsten

Answer 1

+ 1 to the above replies.
An example to pick the column name dynamically from a table and rendering the output of EMP table as a XMLTYPE is here.Pushing it a little bit further, you can project back XML as relational rows and columns :
SQL> with testtable (value1, value2) as (
  2    select 'EMPNO', 'DEPTNO' from dual
  3  )
  4  select x.*
  5  from testtable t
  6     , xmltable(
  7         'for $r in fn:collection("oradb:/SCOTT/EMP")/ROW
  8          return element r {
  9            $r/*[local-name()=$v1]
10          , $r/*[local-name()=$v2]
11          }'
12         passing t.value1 as "v1"
13               , t.value2 as "v2"
14         columns value1 varchar2(30) path '*[1]'
15               , value2 varchar2(30) path '*[2]'
16       ) x
17  ;
VALUE1                         VALUE2
7369                           20
7499                           30
7521                           30
7566                           20
7654                           30
7698                           30
7782                           10
7839                           10
7844                           30
7900                           30
7902                           20
7934                           10
12 rows selected