Selecting one arbitrarily chosen row from each group

Hi,

i try to find a query for selecting one arbitrarily chosen row from
each group of rows.

Example:

$ db2 "select * from T"

A           B           C
----------- ----------- -----------
        100           1          10
        100          20           2
        101           3           3

  3 record(s) selected.

The result should be a 'Select A From T group by A' but with one (B,C)-
pair for each group.

So {(100, 1, 10), (101, 3, 3)} and {(100, 20, 2), (101, 3, 3)} would
both be valid results, but not {(100, 1, 2), (101, 3, 3)}.

Is there a way to formulate this in SQL?

Thanks,
Ralf