SQLite Exception: no such column modified: , while compiling :SELECT _id1 lists from lists .?

I got this problem and I search for solution,but got nothing.I can't figure out why,code is below

    开发者_如何学PythonDEFAULT_SORT_ORDER = "modified DESC"  

   String orderBy;
    if (TextUtils.isEmpty(sortOrder)) {
        orderBy = Momentum.DEFAULT_SORT_ORDER;
    } else {
        orderBy = sortOrder;
    }
    SQLiteDatabase db = mContentHelper.getReadableDatabase();

    Cursor c = qb.query(db, projection, selection, selectionArgs, null,
            null, orderBy);
    c.setNotificationUri(getContext().getContentResolver(), uri);
    return c;

You are ordering by a column named "modified" but it seems you don't have a column named modified, as the error clearly states. Check your db creation to make sure you indeed added this column.