>i don't know if you consider padl() and allt() as less-standard vfp functions (you probably do), but howabout

>index on iif(!Isalpha(CatNumber), padl(allt(CatNumber), FldLength, "0"), CatNumber) tag CatNumber

Being very rusty and none-too-good even years ago, I've been going through the Access functions to see what I can find. In Access:

LEFT is fine after all. TRIM is also fine. I haven't found a PAD yet, but there's got to be one, I would think. IIF is of course good, that's the only one I knew to begin with.

Anyway: your index is *almost* right, but still has the disorder among the alphas...like B1,B13,B2