如何为Android应用程序按降序排列我的SQLITE数据库？

以降序显示数据的最有效方法是什么？

public String getRank() {

    String[] rank = new String[]{ KEY_ROWID };
    Cursor c = scoreDb.query(DATABASE_TABLE, rank, null, null, null, null, null);   //reading information from db.
    String rankResult = "";

    int iRow = c.getColumnIndex(KEY_ROWID); //Cursor looking for column setting equal to these ints.


    for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { 
        //Move to first row - where cursor starts and moves to next row as long it is not after last row.
        rankResult = rankResult + c.getString(iRow) + "\n"; 
        //Returning value of row that it is currently on.
    }
    return rankResult;  //returning result
}

public String getName() {

    String[] name = new String[]{ KEY_NAME };
    Cursor c = scoreDb.query(DATABASE_TABLE, name, null, null, null, null, null);   //reading information from db.
    String nameResult = "";

    int iRow1 = c.getColumnIndex(KEY_NAME); //Cursor looking for column setting equal to these ints.


    for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { 
        //Move to first row - where cursor starts and moves to next row as long it is not after last row.
        nameResult = nameResult + c.getString(iRow1) + "\n"; 
        //Returning value of row that it is currently on.
    }
    return nameResult;  //returning result
}

public String getScore() {

    String[] score = new String[]{ KEY_SCORE };
    Cursor c = scoreDb.query(DATABASE_TABLE, score, null, null, null,null, null);   //reading information from db.
    String scoreResult = "";

    int iRow2 = c.getColumnIndex(KEY_SCORE); //Cursor looking for column setting equal to these ints.


    for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { 
        //Move to first row - where cursor starts and moves to next row as long it is not after last row.
        scoreResult = scoreResult + c.getString(iRow2) + "\n"; 
        //Returning value of row that it is currently on.
    }
    return scoreResult; //returning result
}

查询有两种语法，您正在使用的语法，最后一列表示orderBy，您只需要指定要在哪一列上执行orderBy +“ ASC”（或）orderBy +“ DESC”

Cursor c = scoreDb.query(DATABASE_TABLE, rank, null, null, null, null, yourColumn+" DESC"); 

请参考本文档以了解有关query()方法的更多信息。

Cursor c = scoreDb.query(Table_Name, score, null, null, null, null, Column+" DESC");

尝试这个

return database.rawQuery("SELECT * FROM " + DbHandler.TABLE_ORDER_DETAIL +
                         " ORDER BY "+DbHandler.KEY_ORDER_CREATED_AT + " DESC"
                         , new String[] {});

根据文档：

public Cursor query (String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit);

并且您的ORDER BY参数意味着：

如何对行进行排序，格式为SQL ORDER BY子句（不包括ORDER BY本身）。传递null将使用默认的排序顺序，该顺序可能是无序的。

因此，您的查询将是：

 Cursor cursor = db.query(TABLE_NAME, null, null,
            null, null, null, KEY_ITEM + " DESC", null);

public List getExpensesList(){
    SQLiteDatabase db = this.getWritableDatabase();

    List<String> expenses_list = new ArrayList<String>();
    String selectQuery = "SELECT * FROM " + TABLE_NAME ;

    Cursor cursor = db.rawQuery(selectQuery, null);
    try{
        if (cursor.moveToLast()) {

            do{
                String info = cursor.getString(cursor.getColumnIndex(KEY_DESCRIPTION));
                expenses_list.add(info);
            }while (cursor.moveToPrevious());
        }
    }finally{
        cursor.close();
    }
    return expenses_list;
}

这是我从数据库中读取记录以降序排列的方式。提取每个记录后，将光标移至最后一个并移至上一个记录。希望这会有所帮助〜

Cursor c = myDB.rawQuery("SELECT distinct p_name,p_price FROM products order by Id desc",new String[]{});

这对我有用！！！

你可以做到这一点

Cursor cursor = database.query(
            TABLE_NAME,
            YOUR_COLUMNS, null, null, null, null, COLUMN_INTEREST+" DESC");

SQLite ORDER BY子句用于根据一个或多个列以升序或降序对数据进行排序。游标c = scoreDb.query（DATABASE_TABLE，rank，null，null，null，null，yourColumn +“ DESC”）;

SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.query(
            TABLE_NAME,
            rank,
            null,
            null,
            null,
            null,
            COLUMN + " DESC",
            null);

我们还有一个选项可以通过

public Cursor getlistbyrank(String rank) {
        try {
//This can be used
return db.`query("tablename", null, null, null, null, null, rank +"DESC",null );
OR
return db.rawQuery("SELECT * FROM table order by rank", null);
        } catch (SQLException sqle) {
            Log.e("Exception on query:-", "" + sqle.getMessage());
            return null;
        }
    }

您可以使用这两种方法订购

关于有效的方法。您可以使用CursorLoader。例如，我包括了我的行动。而且，您必须为数据库实现ContentProvider。https://developer.android.com/reference/android/content/ContentProvider.html

如果实施此方法，则将非常高效地称为数据库。

public class LoadEntitiesActionImp implements LoaderManager.LoaderCallbacks<Cursor> {

   public interface OnLoadEntities {
       void onSuccessLoadEntities(List<Entities> entitiesList);
   }

    private OnLoadEntities onLoadEntities;

    private final Context context;

    private final LoaderManager loaderManager;

    public LoadEntitiesActionImp(Context context, LoaderManager loaderManager) {
        this.context = context;
        this.loaderManager = loaderManager;
    }

    public void setCallback(OnLoadEntities onLoadEntities) {
        this.onLoadEntities = onLoadEntities;
    }

    public void loadEntities() {
        loaderManager.initLoader(LOADER_ID, null, this);
    }

    @Override
    public Loader<Cursor> onCreateLoader(int id, Bundle args) {
        return new CursorLoader(context, YOUR_URI, null, YOUR_SELECTION, YOUR_ARGUMENTS_FOR_SELECTION, YOUR_SORT_ORDER);
    }

    @Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
    }

    @Override
    public void onLoaderReset(Loader<Cursor> loader) {
    }

这太可怕了！花了我几个小时！这是我的表行：

private String USER_ID = "user_id";
private String REMEMBER_UN = "remember_un";
private String REMEMBER_PWD = "remember_pwd";
private String HEAD_URL = "head_url";
private String USER_NAME = "user_name";
private String USER_PPU = "user_ppu";
private String CURRENT_TIME = "current_time";

Cursor c = db.rawQuery("SELECT * FROM " + TABLE +" ORDER BY " + CURRENT_TIME + " DESC",null);

每次更新表时，都会更新CURRENT_TIME进行排序。但是我发现这是行不通的。结果没有按我想要的排序。最后，我发现列“ current_time”是sqlite的默认行。

解决方法是，将列“ cur_time”重命名，而不是“ current_time”。