drs = DataTables("商品").Select("[名称] = '风扇')for i as integer = 0 to drs.count-1
if i = 0 then
drs(i)("money") = drs(i)("金额")
else
drs(i)("money")=drs(i)("金额")-drs(i-1)("金额")+drs(i-1)("money")
end if
next