>>In a full join having the fastest way to calc each line may be important.
>>I'm pretty sure that

select nvl(T.PK, P.PK) as PK, nvl(T.FK, P.FK) AS FK, P.pNo, P.pDesc, T.tno, T.tDesc;
>>from Parts P full join Tools T on P.PK = T.PK and P.FK = T.FK into cursor csrToolsParts
>>
>>

>>is easier on resources and for my taste on the eyes as well ;-)
>
>I'm not exactly sure how does it work. It should work only if for each Main table PK we have sequence numbering without gaps, e.g.
>
>Main PK = 1
>FK = 1, 2, 3 in both tables.

Me neither - full join reasons are rare. At least half full joins I encountered were bugs.
But remapping iif(isnull(T.key), p.key, T.key) should not create problems.