I guess the thing to do is to read teh BoL page referenced, plus read the explanation for Paul's 1Nov QotD, the explanation for my 30 Nov QotD, and the explanation for my 5 Dec QotD before attempting to understand this one. Ordering of SQL_VARIANT is pretty complex, and it seems that a lot of people find the very brief explanation in BoL unhelpful (hence my rather verbose explanation for the 5 Dec QotD).