如何使用FirebaseDatabase进行查询？

Question

我的数据库看起来像这样

要获取项目我这样做：

        mFirebaseDatabase
                        .getReference("credits")
                        .orderByChild("regionId")
                        .equalTo(2607)
                        .addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {
                        List<Credit> creditList = new ArrayList<Credit>();

                        for (DataSnapshot postSnapshot : dataSnapshot.getChildren()) {
                        Credit credit = postSnapshot.getValue(Credit.class);
                        creditList.add(credit);
                         }
                    }
                });

1. 如何查询“where regionId == 2607 OR regionId == 0”？
2. 如何查询“where”requiredDocuments'.contains（“Passport”）“？