how to solve this problem

Dear users,
I have this problem

I have a table where there are 20 columns named
vinc1, vinc2, vinc3, vinc4, etc....

the values contained into each column are simply 1 or 0 (each column is
dichotomic)
1 means presence
0 means absence

I would obtain a column (new_column) containg the name of the columns,
comma separated, where the value is = 1

for example:

vinc1 vinc2 vinc3 vinc4 new_column
1 0 1 0 vinc1,vinc3
0 0 0 1 vinc4
0 1 1 1 vinc2,vinc3,vinc4

can someone help me to find the best way to obtain this result???
thank you very much

Ivan

--
Ivan Marchesini
Department of Civil and Environmental Engineering
University of Perugia
Via G. Duranti 93/a
06125
Perugia (Italy)
e-mail: marchesini(at)unipg(dot)it
ivan(dot)marchesini(at)gmail(dot)com
tel: +39(0)755853760
fax: +39(0)755853756
jabber: geoivan73(at)jabber(dot)org