I was looking for an answer to the same question when I stumbled across this thread. Unfortunately, no-one has really answered the question here but I did find a very simple answer elsewhere so will post it here.
Code:
INSERT [INTO] tablename1 (field1, field2, field3, field4)
SELECT field1, field2, field3, A_VALUE dummy_field
FROM tablename2
Here we are inserting into tablename1 some values from the corresponding fields field1,...