It's an odd concept to get your head around, but I think the first query would be the same as doing:
Code:
"SELECT Surname & Chr(44) & Chr(32) & Forenames " & _
  "AS FullName, IIF(IsNull(RegMem.MemID), ""N"", ""Y"") " & _
  "AS Present FROM Members, RegMem WHERE SDate = #" & _
  Format("2005-04-07", "yyyy-mm-dd") & "# AND " & _
  "Members.MemID = RegMem.MemID;"
Thanks for your help.