Android SQLite query where column is not null and not empty

I cannot figure out the syntax for the .query call. I need to select all records that match a certain column that do not have a null or empty value for a second (different) column

my best attempt:

Cursor cursor = mDatabase.query(DatabaseOpenHelper.TABLE_ROOMS, mAllColumns,
    DatabaseOpenHelper.KEY_ROOM_HOSPITAL_ID
    + " =? AND " + DatabaseOpenHelper.KEY_ISO + " IS NOT NULL OR NOT ?",
    new String[]{String.valueOf(hospitalId), ""}, null, null, null);

This is returning ALL records. If I use AND in place of OR, it returns records matching hospitalId, but ignores the NOT NULL OR NOT "" part.

Any tips? Should I use a rawQuery call? Thank you.