propblem with SQLite query?

i have a propblem with this code. but i dont know why

public Cursor fetchReminderByLabel(String table_name, String label,
        String key_column_two) throws SQLException {
    Cursor mCursor = mDb.query(true, table_name, null, key_column_two
            + "=" + label, null, null, null, null, null);
    if (mCursor != null) {
        mCursor.moveToFirst();
    }
    return mCursor;
}

i have an error like no such column label. how can i solve it.