Question

在SQL中，我可以使用IN运算符和子查询，如下所示：

SELECT * FROM t1
WHERE (t1.some_int, t1.some_string) IN (
    SELECT id, name FROM t2
)

但我无法将其转换为SQLAlchemy查询。据我所知，in_方法仅适用于一列。有没有办法在SQLAlchemy中复制这个功能？

Answer 1

您可以使用JOIN而不是子查询。像这样：

在sqlalchemy中：

T1：

SELECT * FROM t1 INNER JOIN t2 ON t1.some_int = t2.id AND t1.some_string = t2.name

T2：

class T1(DeclarativeBase):
    __tablename__ = 't1'

    __table_args__ = {'mysql_engine': 'InnoDB'}

    id = Column(u'id', Integer, primary_key=True)
    some_int = Column('some_int', Integer)
    some_str = Column('some_str', String(45))

    def __init__ (self, some_int, some_str):
        self.some_int = some_int
        self.some_str = some_str

源代码：

class T2(DeclarativeBase):
    __tablename__ = 't2'

    __table_args__ = {'mysql_engine': 'InnoDB'}

    id = Column(u'id', Integer, primary_key=True)
    name = Column('name', String(45))
    data = Column('data', String(45))

    def __init__ (self, name, data):
        self.name = name
        self.data = data

在结果引擎中生成sql：

data = session.query(T1).join(T2, and_(T1.some_int == T2.id, T1.some_string == T2.name)).all()

SQLAlchemy：过滤子查询中的多个列值

1 个答案: