Android中的sqlite查询数据时去掉重复值的方法实例

1、方式一：

    
    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);

全部查询代码如下：

  
  public List getScenicAreas(String areaName){
    ArrayList scenicSpotList = new ArrayList<>();
    String model = "0";
    SQLiteDatabase readableDatabase = mSmartTourSQLiteOpenHelper.getReadableDatabase();
    
    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;
  }

方式二：

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

完整代码：

 
 public static List queryTypeNames() {
 synchronized (DatabaseHelper.lock) {
  List 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();
   }
   if (type != null && type.length() > 1) {
   types.add(type);
   }
  }
  db.close();
  return types;
  } catch (Exception e) {
  db.close();
  }
  return types;
 }
 }

总结

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