在列定义上使用默认值

id = Column(Integer, default = sqlexpression)

其中sqlexpression可以是sql表达式。这是文档 。对于自动增量，您应该使用SQL表达式 coalesce（从order，0中选择max（order.id）+ 1 。为简便起见，您可以导入sqlalchemy.sql.text，以便id列看起来像

Where sqlexpression can be a sql expression. Here is the documentation. For autoincrement you should use the sql expression coalesce(select max(order.id) from order,0) + 1. For ease you could import sqlalchemy.sql.text so the id column could look something like

id = Column(Integer, default = text("coalesce(select max(order.id) from order,0) + 1"))