I would like to arrange in ascending order the average of two fields af1 and af2
the solution would be index on af1+af2 to highave

the problem is that some of the records do not have an af2 so for these I would need the index to still place the highest of af1
together with the averaged af1+af2

is there a way to set up the index such that if af2 =0 then index on af1 only, if af2>0 the index on af1+af2

Can you please let me know if this is possible and a suggestion on how to formulate the code to create this double index

thanks
k