SQL 查询选择计数(*) AS 分组

Question

有人可以帮助我从表中取出分组产品的数量，并将它们传递给回收者视图吗？ 我的代码可以很好地处理简单的查询，但是当我想对分组数据进行计数时，它不起作用 我希望你可以帮助我。非常感谢！！

我正在使用 Android Studio Giraffe | 2022.3.1 补丁 2

这是我无法解决的代码部分

public class DbDBMaster extends DbHelper {

    Context context;

    
   public ArrayList<Products> takeAmount() {

        DbHelper dbHelper = new DbHelper(context);
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        ArrayList<Products> listProducts= new ArrayList<>();
        Products products;
        Cursor cursorProducts;
    // This works fine: cursorProducts = db.rawQuery("SELECT * FROM " + TABLE_MYDBProducts+ " GROUP BY numberProd ", null);
        cursorProducts = db.rawQuery("SELECT COUNT(*) AS amount,numberProd, nameProd FROM " + TABLE_MYDBProducts+ " GROUP BY numberProd ", null);

        if (cursorProducts.moveToFirst()) {
            do {
                products = new Products();
                products.setAmount(cursorProducts.getInt(0));
                products.setNumberProd(cursorProducts.getString(1));
                products.setNameProd(cursorProducts.getString(2));
                listProducts.add(products);
            } while (cursorProducts.moveToNext());
        }
        cursorProducts.close();
        return listProducts;
    }
}

当我想统计分组数据时，它不起作用

Answer 1

尝试以下操作：

GROUP BY numberProd, nameProd

如果有效请告诉我们