can use this
Dim intID As Integer
Dim isHAVE As Integer
isHAVE = (From Tbl In db.tblRSInterests Select Tbl.intTrxId).Count()
If (isHAVE = 0) Then
intID = 1
Else
intID = (From Tbl In db.tblRSInterests Select Tbl.intTrxId).Max() + 1
End If
if any one have thing better till me