public static Field p(String fieldName) {
        return SELECT_ALL_FROM_SOURCES_ALL.where(fieldName);
    }
@Test
    void empty_queries_should_not_print_out() {
        String q = Q.p(Q.p(Q.p().andnot(Q.p()).and(Q.p()))).and("a").contains("1").build();

        assertEquals(q, "yql=select * from sources * where a contains \"1\"");
    }