string concatenation

hi there,


i have two column c1 and c2

in a select statement i concatenate both of them:

select c1&', '&c2 from tbl

here my problem: if one of the columns is null, the concatenated string c1&'
'&c2 is also null, no matter what the other column contains.


is there another way to concatenate two columns in a select statement? maybe
an sth. like

if(c1 is null)
then c2
else c1&', '&c2


??



thx
J