Do we have a function in oracle to select not null columns at the begining

Question

Hi,
I have 8 columns. Some of them might be null.
I want to display all 8 columns in my result. Not null columns will be first and null at the end.
Here is a sample data :
Employee table :
Employee_id   Emp_fname  emp_lname  emp_mname  dept salary emp_height  emp_weight
   1               aaa        ddd                d1   100      6           180
   2               bbb                ccc             120                 169
   3               dfe                           d2            5.9         223The expected result is :
result1 result2   result3 result4  result5  result6 result7 result8
1        aaa        ddd     d1       100     6        180
2        bbb        ccc     120      169
3        dfe        d2      5.9      223Thanks.
Edited by: BluShadow on 12-Jul-2012 16:12
added {noformat}{noformat} tags for readability.  Please read {message:id=9360002} and do this yourself in future.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

The requirement doesn't make a lot of sense and tends to imply that you have an incorrect data model. If that's the case, you'd be much better off fixing the data model than in trying to write this sort of query (particularly since a poor data model is going to force you to write a bunch of creative SQL).
If you define a type and a function
CREATE TYPE num_tbl AS TABLE OF NUMBER;
create or replace function count_null( l_nums in num_tbl )
  return number
is
  l_cnt integer := 0;
begin
  for i in 1..l_nums.count
  loop
    if( l_nums(i) is null )
    then
      l_cnt := l_cnt + 1;
    end if;
  end loop;
  return l_cnt;
end;Then you can do something like this
SQL> ed
Wrote file afiedt.buf
  1  select product,
  2         coalesce( q1, q2, q3, q4 ) col1,
  3         (case when count_null( num_tbl( q1 ) ) = 0
  4               then coalesce( q2, q3, q4 )
  5               when count_null( num_tbl( q1, q2 ) ) = 1
  6               then coalesce( q3, q4 )
  7               when count_null( num_tbl( q1, q2, q3 ) ) = 1
  8               then q4
  9               else null
10           end) col2,
11         (case when count_null( num_tbl( q1, q2 ) ) = 0
12               then coalesce( q3, q4 )
13               when count_null( num_tbl(q1, q2, q3) ) = 1
14               then q4
15               else null
16           end) col3,
17         (case when count_null( num_tbl( q1, q2, q3 ) ) = 0
18               then q4
19               else null
20           end) col4
21*   from saleshist
SQL> /
PRODUCT                              COL1       COL2       COL3       COL4
Oracle EE                             100        123        128
Partitioning                          100        130        128Justin