Vladimir Oselsky shows how to use THROW and RAISERROR for rethrowing exceptions:
Upon executing the first procedure, we get the error message back to the front end, but after checking balance, we find that money withdrawn from the account, but in the case of the second procedure, the same error returned to the front end but money still there.
Now we begin to scratch our head trying to figure out why we lost the money even though we got errors in both cases. The truth behind is the fact that RAISERROR does not stop the execution of code if it is outside of TRY CATCH block. To get same behavior out of RAISERROR, we would need to rewrite procedure to look something like following example.
There are some nuanced differences between THROW and RAISERROR, so it’s valuable to know how both work.