How can I move a Blob from one table to another without transferring
it over the network?

Is that possible?

update table2
set myblobfield =
(select anotherblobfield from table1 where id=...)

or is there a better way to do it?

Will it create another instance of the blob or just copy the blob
"pointer"? So if I overwrite the blob in table1 after that, will the
blob in table2 also change or not?

Regards

Stefan