>I have the following command:
>
>

>UPDATE Invoices;
>  SET InvoiceId = "ABC123";
>  WHERE RecordId IN;
>    (SELECT RecordId
>     FROM Invoices2)
>
>

>
>
>
>1) Does VFP first create a subset of Invoices2.RecordId and then use that
>to drive the update Invoices? Or is each record in Invoices2 evaulated
>for every record in Invoices?
>
>2) Is there a more efficient way to do this?
>
>Thanks

VFP first create a subset of Invoices2.RecordId and then use that to drive the update Invoices.
There are other ways but mostly xbase based. ie:

UPDATE Invoices;
  SET InvoiceId = "ABC123";
  WHERE seek(RecordId,'Invoices2','recordId')

Cetin