SQL中的CASE

#region 返回型号数据
  ///<summary>
  /// 返回型号数据
  ///</summary>
  ///<returns></returns>
  public static DataTableGetBearing(string beAppID)
  {
   stringsql="selecta.BearingID,a.BeAppID,a.BearingNo,a.BearingType,a.BearingMemo,a.SequenceIndex,"
     +" (CASE a.BearingType WHEN 0 THEN '国标' WHEN 1 THEN '非标' ELSE ''END) AS BearingTypeName, "
     +"b.BeBaseID,b.BeBaseNewNo,b.BeBaseOldNo,b.BeBaseIDiameter,b.BeBaseODiameter,b.BeBaseBreadth"
     +" from T_BAS_Bearing as a inner join T_BAS_BeBase as b ona.BearingID=b.BearingID "
     +" Where a.DelFlag = 0 And b.DelFlag = 0 And a.BeAppID='"+ beAppID+"' Order by a.SequenceIndex,a.BearingNo";
   returnExecute.ExecuteDataTable(sql);
  }
  #endregion