display sum using alv grid control

hi,

am using cl_gui_alv_grid for displaying.

i tried by selecting all fields for sample and i got it.

but when i tried to have limited fields for this i used fieldcat of type lvc_t_fcat am not getting and also i tried to have total on one field.

am not getting total and limited fields output.

the report is displaying all the fields but the content will be only for the fields i selected in fcat.

i need only some fields and have total on one field.

please help...