In this case, a speed test on arnelgp's #17 would be on what is PROBABLY the fastest choice, but with the understanding that the general case might be content-sensitive i.e. speed will depend on the number of nulls involved. The ampersand will try to concatenate something but it has to test first whether there IS anything to concatenate. Therefore there is a two-step process, the second step of which will be skipped when there IS a null in a field. (Actually, three two-step processes, one for each field.) Therefore the speed test would be expected to show a wider range of timing.