Rollback and Raiseerror, which first?
It would matter if you were in a TRY-CATCH block - the raiserror would divert execution to the catch block, so if the rollback came after it (within the try block) then it would not execute.
Also it would depend on the severity of the error - severity 20+ terminates the database connection.
A nice pattern to use is something like
begin try begin transaction; -- do stuff commit transaction;end trybegin catch declare @ErrorMessage nvarchar(max), @ErrorSeverity int, @ErrorState int; select @ErrorMessage = ERROR_MESSAGE() + ' Line ' + cast(ERROR_LINE() as nvarchar(5)), @ErrorSeverity = ERROR_SEVERITY(), @ErrorState = ERROR_STATE(); if @@trancount > 0 rollback transaction; raiserror (@ErrorMessage, @ErrorSeverity, @ErrorState);end catch