如何从sqlalchemy获取嵌套的JSON？

如何解决如何从sqlalchemy获取嵌套的JSON？

我正在使用flask-restful和flask-sqlalchemy和flask_marshmallow。这是我的代码：

表结构：

class Product(db.Model):

    __tablename__ = 'product'
    product_id = db.Column(db.Integer,primary_key=True)
    title = db.Column(db.String(100))
    description = db.Column(db.Text)
    sale_price = db.Column(db.Float)
    logo = db.Column(db.String)
    featured = db.Column(db.Text,default='ok')
    status = db.Column(db.Text,nullable=True)
    add_timestamp = db.Column(db.Text,default=datetime.utcNow)
    number_of_view = db.Column(db.Integer,default=0)
    category = db.Column(db.Integer,default='')
    sub_category = db.Column(db.Integer,nullable=True,default='')
    additional_fields = db.Column(db.Text,default='')

class PostSchema(ma.Schema):
    class Meta:
        fields = ('product_id','title','description','sale_price','logo','featured','status','add_timestamp','number_of_view','sub_category_id','sub_category_name','brand','digital','category','banner','affiliation','affiliation_points','category_id','category_name','data_brands','data_vendors','data_subdets','additional_fields')

这是api：

class Test1(Resource):
    def get(self):
        return posts_schema.dump(Product.query.all())

api.add_resource(Test1,'/products/test1')

这是我得到的输出：

{
        "add_timestamp": "1581791188","additional_fields": "{\"name\":\"[\\\"Uses\\\",\\\"Tags\\\"]\",\"value\":\"[\\\"<p>A shipping company,A music brand,An app,A gadget <br><\\\\\/p>\\\",\\\"<p>5-Letter Names,\\\  Creative & Brandable Names,Operations,Software & Technology <br><\\\\\/p>\\\"]\"}","category": 12,"featured": "0","number_of_view": 2077,"status": "ok","title": "Crax"
    }

我想将“ additional_fields”放入嵌套的json。还要删除HTML标签。请帮帮我。