将您的
expression部分更改为:
@number_of_requests.expressiondef number_of_requests(cls): return (select([func.count(Request.id)]) .where(Request.cover_id == cls.id))
再读
Correlated Subquery RelationshipHybrid一遍。

将您的
expression部分更改为:
@number_of_requests.expressiondef number_of_requests(cls): return (select([func.count(Request.id)]) .where(Request.cover_id == cls.id))
再读
Correlated Subquery RelationshipHybrid一遍。