删除了没用的objRst,补充定义了几个变量，在WinCC V6.0里测试通过
Dim strCon,strSQL
Dim objCon,objCommand,objRecordset,lngCount,lngValue
Dim oList,oItem
Dim Number,i
strCon="DRIVER={SQL server};SERVER=.\WinCC;DATABASE=CC_demo_12_06_19_21_42_57"
strSQL="Select gkrong from gkrong_demo "
Set objCon=CreateObject("ADODB.Connection")
objCon.ConnectionString = strCon
objCon.Open
Set objCommand = CreateObject("ADODB.Command")
Set objCommand.ActiveConnection = objCon
objCommand.CommandText = strSQL
Set objRecordset = objCommand.Execute
lngCount = objRecordset.Fields.Count
If (lngCount>0) Then
objRecordset.movefirst
lngValue = objRecordset.Fields(0).Value
HMIRuntime.Tags("demo").Write lngValue
Else
HMIRuntime.Trace "Selection returned no fields" & vbNewLine
End If
HMIRuntime.Trace strSQL
objRecordset.Close
Set objRecordset = Nothing
Set objCommand = Nothing
objCon.Close
Set objCon = Nothing