def get_data(variation=None, brand=None, page=None):
    q = self.session.query(TableName)
    if variation:
        q = q.filter(TableName.variation == variation)
    if brand:
        q = q.filter(TableName.brand == brand)
    if page:
        q = q.limit(page * pageSize)
    return q.all()

这个很简单啊

variation = request.args.get('variation')
brand = request.args.get('brand')

这样获取需要的参数，空的参数这里会返回None

然后使用SQLAlchemy的语法

if variation：
    query = query.filter_by(variation=variation)
if brand：
     query = query.filter_by(brand=brand)