UNION di due tabelle differenti

[Grinder]

E' possibile unire due tabelle aventi campi diversi e ordinare il tutto per un campo qualsiasi di una delle due?

Sto provando così:

select case request.QueryString("ord")
	case "1a"
		ordina = " ORDER BY codart ASC"
	case "2a"
		ordina = " ORDER BY desart ASC"
	case "3a"
		ordina = " ORDER BY promo ASC"
	case "4a"
		ordina = " ORDER BY codfor ASC"
	case "5a"
		ordina = " ORDER BY preart2 ASC"
	case "8a"
		ordina = " ORDER BY disp ASC"
	case "9a"
		ordina = " ORDER BY ofor ASC"
	case "10a"
		ordina = " ORDER BY nart ASC"
	case "1d"
		ordina = " ORDER BY codart DESC"
	case "2d"
		ordina = " ORDER BY desart DESC"
	case "3d"
		ordina = " ORDER BY promo DESC"
	case "4d"
		ordina = " ORDER BY codfor DESC"
	case "5d"
		ordina = " ORDER BY preart2 DESC"
	case "8d"
		ordina = " ORDER BY disp DESC"
	case "9d"
		ordina = " ORDER BY ofor DESC"
	case "10d"
		ordina = " ORDER BY nart DESC"
end select

SELECT * FROM newecom UNION (SELECT * FROM ordini) WHERE codart IN("& Left(strSQL, len(strSQL)-1) &")"&ordina&"

peccato non funzioni...