GROUP BY query in SQL?

Question

I am new to implementing sql in android I need to show a list after storing the data into my localdb below is my code snippet

 private void getAllData() {
    data.clear();

    Cursor mCursr_all = SFMApp.localDBS.fetchMyPurchaseAllGroupBy(activity, SFMTableCreate.TABLE_SFM_STORE_MYPURCHASE, null);
    Log.e("mCursor","::::::"+mCursr_all.getPosition()+":::::"+mCursr_all.getColumnNames());
    data.addAll(new SFMCursorFactory().fetchMyPurchaseMaster(mCursr_all, SFMTableCreate.getColoumnArrayCallMYPURCHASE()));
    if (mCursr_all == null) {
        //Toast.makeText(activity,"Cursor value is null",Toast.LENGTH_SHORT).show();
    } else {
        for (int i = 0; i <data.size() ; i++) {

            String data1 = data.get(i).getPurchaseNo();
            Log.e("PURCHASE Key:::::","::::::::====="+data1);

        }

        purchaseAdapter = new SFMMyPurchaseAdapter(activity, data,SFMMyPurchase.this);
        callloglist.setAdapter(purchaseAdapter);

    }
    dismissProgress();
}

here in the above code data is my arraylist of my data model fetchMyPurchaseAllGroupBy function is below

public Cursor fetchMyPurchaseAllGroupBy(Context context, String table, String[] columns) {
    SQLiteDatabase db = context.openOrCreateDatabase(
            SFMAppConfig.DB_NAME, SQLiteDatabase.OPEN_READWRITE, null);
    String query;
    query = "Select * from " + table + " GROUP BY "+SFMTableCreate.COLOUMNS_SFM_CALL_MYPURCHASE.PurchaseKey.name();
    Log.e("Query", query);
    Cursor mCursor = db.rawQuery(query, null);

    /*Cursor mCursor = db.query(table, columns,
            SFMTableCreate.COLOUMNS_SFM_ASSET_TAG_LOG_MASTER.vcCode.name(), null, null, null, SFMTableCreate.COLOUMNS_SFM_ASSET_TAG_LOG_MASTER.vcCode.name() + " DESC");*/
    if (mCursor != null && mCursor.getCount() != 0 && mCursor.moveToFirst()) {
        Log.e("fetchAll", "notNull");
        Log.e("row count", "" + mCursor.getCount());
    } else {
        Log.e("fetchAll", "Null");
        mCursor = null;
    }
    db.close();
    return mCursor;
}

and fetchMyPurchaseMaster func is below

 public ArrayList<MyPurchaseData> fetchMyPurchaseMaster(Cursor mCursor, String[] columns) {
    ArrayList<MyPurchaseData> aData = new ArrayList<MyPurchaseData>();

    if (mCursor == null)
        return aData;
    int[] columnIndex = new int[columns.length];

    for (int i = 0; i < columnIndex.length; i++)
        columnIndex[i] = mCursor.getColumnIndex(columns[i]);
        Log.e("ColumnIndex",":::::"+columnIndex);

    do {
        MyPurchaseData data = new MyPurchaseData();
        int j = 0;
        data.setPurchaseKey(mCursor.getInt(columnIndex[j++]));
        data.setPurchaseDate(mCursor.getString(columnIndex[j++]));
        data.setPurchaseNo(mCursor.getString(columnIndex[j++]));
        data.setNetAmount(mCursor.getInt(columnIndex[j++]));
        data.setVendorName(mCursor.getString(columnIndex[j++]));
        data.setItemName(mCursor.getString(columnIndex[j++]));
        data.setUnit(mCursor.getString(columnIndex[j++]));
        data.setQTY(mCursor.getInt(columnIndex[j++]));
        data.setRATE(mCursor.getInt(columnIndex[j++]));


        j = 0;
        aData.add(data);
    } while (mCursor.moveToNext());

    Log.e("cursor size", String.valueOf(aData.size()));

    return aData;
}

below is how my screen should look like

my json response link http://mobile.spectrafm.com/SPFMWEBAPI2/api/Stores/GetPurchaseList/03/2018/SPFM002

here please help me how to use GROUPBY query and make the screen appear like the image above given

Note currently am getting as