Hi Thom,
Appreciate the reply. Essentially no, there isn't a NULL getting passed as [TABLE123].[accountnum1] also doesn't allow NULLS and all the values contained in that table after the batch does its updates/inserts are valued account numbers.
Can you possibly explain "Also, I hope that your process never updates or inserts more than 1 row at a time, or the above trigger will not work as expected"?? This should be straightforward, but has me confused.
(I 'obfuscated' the true table and column names above, so hopefully I have not done it incorrectly)