Postgresql Sqlalchemy相交和除外

有人知道如何将这些原始SQL查询转换为sqlalchemy吗

new_records = db.session.execute('SELECT issn_l, issn FROM issn_temp EXCEPT SELECT issn_l, issn FROM issn_to_issnl;')

removed_records = db.session.execute('SELECT issn_l, issn FROM issn_temp INTERSECT SELECT issn_l, issn FROM issn_to_issnl;')

我的模型如下：

class ISSNTemp(db.Model):
    __tablename__ = "issn_temp"
    issn_l = db.Column(db.String(9), nullable=False, primary_key=True)
    issn = db.Column(db.String(9), nullable=False, primary_key=True)


class ISSNToISSNL(db.Model):
    __tablename__ = "issn_to_issnl"

    issn_l = db.Column(db.String(9), nullable=False, primary_key=True)
    issn = db.Column(db.String(9), nullable=False, primary_key=True)
    created_at = db.Column(db.DateTime, default=datetime.datetime.utcnow)

---

我尝试使用union，但效果不好。

最近我在附近构建了一个分层查询：

differential_select = union(
    select( *( [ deltakey ] + sncolumns + [ literal( 'SN' ).label( 'op' ) ] ) ).except_(
        select( *( [ deltakey ] + tncolumns  + [ literal( 'SN' ).label( 'op' ) ] ) )
    ),
    select(*( [ deltakey ] + tncolumns + [ literal( 'TN' ).label( 'op' ) ] ) ).except_(
        select( *( [ deltakey ] + sncolumns  + [ literal( 'TN' ).label( 'op' ) ] ) ) 
    )
)

将此应用于您的第一个查询，我得到：

select(
    issn_temp.c.issn_l,
    issn_temp.c.issn
).except_(
    select(
        issn_to_issn.c.issn_l,
        issn_to_issn.c.issn
    )
)

其中，issn_temp和issn_to_issn指向的实例

还要注意，还有更多的细节和细节