我在使用以下查询时遇到了一些问题，我不确定如何修改它以提供我想要的输出，下面将对此进行详细说明:SELECTlistup.NodeNumberAsNode,listup.StationAsExtension,CASEWHENVoiceServer=1THENKeyDescriptionELSE''ENDAS'Key1',CASEWHENVoiceServer=2THENKeyDescriptionELSE''ENDAS'Key2',CASEWHENVoiceServer=3THENKeyDescriptionELSE''ENDAS'Key3',CASEWHENVoiceServer=4