Android: Find All Title without Genre Information

2020-02-15 android

i have code which gives me all genres in the system, where i can afterwards load all song ids. I have additionally implemented the option to load every song through a cursor.

But how can i find titles which have no genre tags and only those? My first hope was that they would be accumulated in a tag "Unknown" but thats seems not be the case.

As i read, the intern android database has no real table column called Genre. MediaStore documentation states:

 * The genre of the audio file, if any
                 * Does not exist in the database - only used by the media scanner for inserts.
                 * @hide
                // @Column(Cursor.FIELD_TYPE_STRING)
                public static final String GENRE = "genre";

My GenreLoader is like this:

   final String[] projection = new String[]{

        try {
            return context.getContentResolver().query(
                    projection, null, null, PreferenceUtil.getInstance(context).getGenreSortOrder());

Can i do sth. really sql-like and join Song-Table with Genre-Table and filter where genre IS NULL? How do i debug sth. like this, where do i find information about the table layout?