Bruce,

>>>Anyway, INLIST() is optimizable, perhaps IN is not, at least not the way it's used here for a list of items.
>>
>> It contradicts with Ed Rauh said in his message, so I checked and found, that INLIST works faster. BTW, I know, that $ is not optimizable function. What about AT()? If they are both non-optimizable, I'd rather change my code to use $ instead of AT(), as I do now, for shortness of sql string.
>
>I didn't read what Ed said, but INLIST was not optimizable until later versions of foxpro, I believe. IN also shows fully optimizable in SQL in a list usage ("value set") with SYS(3054). So it's *supposed* to be fast - but I've never done testing with it, so can't say much else...
>
>Not sure about AT() vs $ - neither are optimizable, and I can only say that I have used $ in some fairly large tables, and it's surprisingly fast. You are welcome to test them and give us back the results :)

I made tests today, I selected from lots of joined tables, which are very huge, and issue expression in where clause like:
('A' $ Amenities or 'B'$ Amenities etc.) - it took 164 sec.
(at('A',Amenities)>0 or at('B',Amenities)>0 etc.) - it took 202 sec. I haven't index on Amenities.
So, my conclusion is that $ works faster than at() (at least, if I haven't index). I'm going to change my code appropriately.