我需要执行以下查询:
select field11, field12
from Table_1 t1
left outer join Table_2 t2 ON t2.tbl1_id = t1.tbl1_id
where t2.tbl2_id is null
我用python编写了以下课程:
class Table1(Base):
....
class Table2(Base):
table_id = Column(
Integer,
ForeignKey('Table1.id', ondelete='CASCADE'),
)
....
我如何从下面到达上面？
q = session.query(Table1.field1, Table1.field2)\
.outerjoin(Table2)\ # use in case you have relationship defined
# .outerjoin(Table2, Table1.id == Table2.table_id)\ # use if you do not have relationship defined
.filter(Table2.tbl2_id == None)
应该这样做，假设field1和field2来自Table1，并且您定义了一种关系:
class Table2(Base):
# ...
table1 = relationship(Table1, backref="table2s")