Distinct Count of Customers

Hi All,

We are following the code given below

triptype customerid
van 24
van 25
bus 24
van 24
van 25

if triptype='van' then
customerid
else
0

We r making distinct count of above formula
now we getting distinct count as 3(Include 24,25 ,0)

but we need distinct count as 2 So there is any solution plz suggest meGroup the report by triptype and Right click on the customerid column; Insert Summary;choose distinct count;