Subject how to combine a field value while their id is same?
Author ibmcom2011
Post date 2011-10-23T14:05:16Z
now i have a table such as:

f1 f2
1 aa
2 tf
1 bb
3 cc
2 ht

i want the result seems as:

f1 f2
1 aa, bb
2 tf, ht
3 cc

any help is appreciated, thanks.