CASE(?) to write in a different column based on a string pattern

Hi,
    I need to create a CASE (I think) statement to check for a string
pattern, and based on its value, write a substring in a different column
(alias).
I'm trying to create a COPY statement to port a table into antoher
database, which has a table with another format (that's why the aliases)

Let's write it in pseudoSQL:

given this

select pattern from tbl;
pattern
----------
foo1234
bar5678
baz9012

That's what I'm trying to achieve

select
    pattern,
        CASE when pattern like 'foo%' then ltrim(pattern, 'bar') as foo
                  when pattern like 'bar%' then ltrim(pattern, 'bar')
as bar
                  when pattern like 'baz%' then ltrim(pattern, 'baz')
as baz
        END
from tbl;

|foo   |bar  |baz |
 1234
            5678
                        9012
(hoping text formatting is ok... 1234 should go in column foo, 568 in
bar and 9012 in baz)

Is it possible?

Thanks in advance
Moreno.-