Question

如何在python中使用sqlalchemy重写以下sql语句。我一直在寻找30分钟，但仍然找不到任何解决方案。

DATEADD(NOW(), INTERVAL 1 DAY)

或

INSERT INTO dates (expire)
VALUES(DATEADD(NOW(), INTERVAL 1 DAY))

提前致谢

Answer 1

为了完整起见，以下是使用sqlalchemy.sql.func生成确切SQL的方法：

from sqlalchemy.sql import func
from sqlalchemy.sql.expression import bindparam
from sqlalchemy import Interval

tomorrow = func.dateadd(func.now(), bindparam('tomorrow', timedelta(days=1), Interval()))

导致：

>>> from sqlalchemy.sql import func
>>> func.dateadd(func.now(), bindparam('tomorrow', timedelta(days=1), Interval(native=True)))
<sqlalchemy.sql.expression.Function at 0x100f559d0; dateadd>
>>> str(func.dateadd(func.now(), bindparam('tomorrow', timedelta(days=1), Interval(native=True))))
'dateadd(now(), :tomorrow)'

或者，您可以使用text()对象来指定间隔：

from sqlalchemy.sql import func
from sqlalchemy.sql.expression import text

tomorrow = func.dateadd(func.now(), text('interval 1 day'))

Answer 2

SQLAlchemy日期自动映射到Python日期时间对象，因此您应该能够：

from sqlalchemy import Table, Column, MetaData, DateTime
from datetime import datetime, timedelta

metadata = MetaData()
example = Table('users', metadata,
   Column('expire', DateTime)
)

tomorrow = datetime.now() + timedelta(days=1)

ins = example.insert().values(expire=tomorrow)

Answer 3

在我打字的时候，Doobeh打败了我，这里有一个烧瓶 - sqlalchemy例子，我打算发帖（赞美简单的sqlalchemy例子）：

from flask.ext.sqlalchemy import SQLAlchemy
from datetime import datetime, timedelta

db = SQLAlchemy()

class Thing(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    created = db.Column(db.DateTime)

c = Thing(created = datetime.utcnow() + timedelta(days=1))
print repr(c.created)
# datetime.datetime(2013, 3, 23, 15, 5, 48, 136583)

您也可以将默认值作为可调用对象传递：

from flask.ext.sqlalchemy import SQLAlchemy
from datetime import datetime, timedelta

db = SQLAlchemy()

def tomorrow():
    return datetime.utcnow() + timedelta(days=1)

class Thing(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    publish_date = db.Column(db.DateTime, default=tomorrow)

Answer 4

您可以使用MySQL timestampadd insted dateadd。

更多细节http://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_timestampadd

Answer 5

from datetime import datetime, timedelta
from dateutil import tz

new_date = datetime.now(tz=tz.tzlocal()) + timedelta(days=1)
new_item = Expire(expire=new_date)
session.save(new_item)
session.commit()

在sqlalchemy中使用DATEADD

5 个答案: