Hugo Kornelis (1/4/2011)
I replied wrong - I saw the rollback after the truncate, assumed the question intended to test my understanding that a truncate can be rolled back, and then replied. I had not seen the missing ALL after the UNION operators, nor noticed the duplicate row.The knowledge tested is good, but the way the question has been built suggests to me that the author tried to trick people into overlooking key elements. It would have been better to make two questions, one about rolling back after truncate table (with no other elements to confuse the reader), and one that uses UNION and inserts a duplicate row (again, with no other elements to distract the reader).
Ditto. learned nothing here. Moreover I "never" use unions to load data into table unless I'm creating test data... especially with 15 manuel inserts.
I think most unknown fact in this question is that the truncate will be rolled back. Not that there's a difference between union and union all.
I would rather have seen a question hammering on the former point rather than the latter.