Android中的sqlite查询数据时去掉重复值的方法实例

    /**
     * 参数一：是否去重
     * 参数二：表名
     * 参数三：columns 表示查询的字段,new String[]{MODEL}表示查询该表当中的模式（也表示查询的结果）
     * 参数思：selection表示查询的条件，PHONE_NUMBER+" = ?" 表示根据手机号去查询模式
     * 参数五：selectionArgs 表示查询条件对应的值,new String[]{phoneNumber}表示查询条件对应的值
     * 参数六：String groupBy 分组
     * 参数七：String having
     * 参数八：orderBy 表示根据什么排序,
     * 参数九：limit 限制查询返回的行数，NULL表示无限制子句
     **/
    Cursor cursor = readableDatabase.query(true,TABLE_NAME, new String[]{DESCRIPTION,ID,IMAGE_URL,LATITUDE,LONGITUDE,NAME,NEED_AUDIO,SPOT_TYPE,TGROUP,AUDIO_NAME,AREA_NAME}, AREA_NAME + " = ?", new String[]{areaName}, null, null, null,null);

  /**
   * 根据景区名称查询景点数据
   * @param areaName
   * @return 0：未查询到拦截模式（也就是该手机号没有设置拦截模式） 1：拦截短信 2：拦截电话 3：拦截所有
   **/
  public List<ScenicSpot> getScenicAreas(String areaName){
    ArrayList<ScenicSpot> scenicSpotList = new ArrayList<>();
    String model = "0";
    SQLiteDatabase readableDatabase = mSmartTourSQLiteOpenHelper.getReadableDatabase();
    /**
     * 参数一：是否去重
     * 参数二：表名
     * 参数三：columns 表示查询的字段,new String[]{MODEL}表示查询该表当中的模式（也表示查询的结果）
     * 参数思：selection表示查询的条件，PHONE_NUMBER+" = ?" 表示根据手机号去查询模式
     * 参数五：selectionArgs 表示查询条件对应的值,new String[]{phoneNumber}表示查询条件对应的值
     * 参数六：String groupBy 分组
     * 参数七：String having
     * 参数八：orderBy 表示根据什么排序,
     * 参数九：limit 限制查询返回的行数，NULL表示无限制子句
     **/
    Cursor cursor = readableDatabase.query(true,TABLE_NAME, new String[]{DESCRIPTION,ID,IMAGE_URL,LATITUDE,LONGITUDE,NAME,NEED_AUDIO,SPOT_TYPE,TGROUP,AUDIO_NAME,AREA_NAME}, AREA_NAME + " = ?", new String[]{areaName}, null, null, null,null);
    while (cursor.moveToNext()){
      ScenicSpot scenicSpot = new ScenicSpot();
      String description = cursor.getString(cursor.getColumnIndex(DESCRIPTION));
      String id = cursor.getString(cursor.getColumnIndex(ID));
      String image_url = cursor.getString(cursor.getColumnIndex(IMAGE_URL));
      String latitude = cursor.getString(cursor.getColumnIndex(LATITUDE));
      String longitude = cursor.getString(cursor.getColumnIndex(LONGITUDE));
      String name = cursor.getString(cursor.getColumnIndex(NAME));
      String need_audio = cursor.getString(cursor.getColumnIndex(NEED_AUDIO));
      String spot_type = cursor.getString(cursor.getColumnIndex(SPOT_TYPE));
      String tgroup = cursor.getString(cursor.getColumnIndex(TGROUP));
      String audio_name = cursor.getString(cursor.getColumnIndex(AUDIO_NAME));
      String area_name = cursor.getString(cursor.getColumnIndex(AREA_NAME));
      scenicSpot.setDescription(description);
      scenicSpot.setId(id);
      scenicSpot.setImageurl(image_url);
      scenicSpot.setLatitude(latitude);
      scenicSpot.setLongitude(longitude);
      scenicSpot.setName(name);
      scenicSpot.setNeedAudio(need_audio);
      scenicSpot.setSpotType(spot_type);
      scenicSpot.setTgroup(tgroup);
      scenicSpot.setAudioname(audio_name);
      scenicSpot.setAreaName(area_name);
      scenicSpotList.add(scenicSpot);
    }
    cursor.close();
    readableDatabase.close();
    return scenicSpotList;
  }

String sql = "select distinct "
   + TYPENAME
   + " from "
   + TABLE_NAME 
   + " ORDER BY " + TYPE + " ASC";
  Cursor c = db.rawQuery(sql, null);

 /**
 * @return 所有组织结构名称
 **/
 public static List<String> queryTypeNames() {
 synchronized (DatabaseHelper.lock) {
  List<String> types = null;
  SQLiteDatabase db = DatabaseHelper.getInstance().getReadableDatabase();
  try {
  String sql = "select distinct "
   + TYPENAME
   + " from "
   + TABLE_NAME 
   + " ORDER BY " + TYPE + " ASC";
  Cursor c = db.rawQuery(sql, null);
  while (c.moveToNext()) {
   String type = c.getString(c.getColumnIndex(TYPENAME));
   if (types == null) {
   types = new ArrayList<String>();
   }
   if (type != null && type.length() > 1) {
   types.add(type);
   }
  }
  db.close();
  return types;
  } catch (Exception e) {
  db.close();
  }
  return types;
 }
 }