I made a small example:
Set rs_Recordset = New ADODB.Recordset
str_Sql = "select * from tbl_MyTable"
str_Sql = str_Sql & " where (selectData = '" & !MyDbField & "')"
rs_Recordset.Open str_Sql, cn_MyDataBase, adOpenDynamic, adLockOptimistic
If Not (rs_Recordset.BOF And rs_Recordset.EOF) Then...