Merge Multiple Rows Into Single Result

Hi,

Does anyone know a way to do the following, given a table like

Field_A, Field_B

a         first word
a         second word
a         third word

then runa group by query on it to merge the contents of field_b seperating with commas.

select field_a, merge(field_b,',')
from table
group by a

resulting in
Field_A New_String
a first word, second word, thrid word Received on Thu Nov 14 2002 - 10:35:37 CST