Е, защо да е по-сложничко с база?
Например:

set Rs = oConn.Execute("SELECT * FROM banners")

strBanners = rs.getrows()
rs.movefirst
Do While Not rs.EOF
intCounter = intCounter + 1
rs.movenext
Loop

Randomize
intID = Int(Rnd * intCounter)
strDisplay = strBanners(1,intID)
------------------------------------------------------
<%= strDisplay%>