SQLAlchemy 查询与多列元组比较

Question

我有一个查询需要在我的应用程序中支持分页。

def get_paginated_items(
        self,
        limit: int,
        last_shipment_time: int = MAX_INT,
        last_item_id: int = MAX_INT,
    s = (
        select([self.items])
        .where((
            self.items.c.shipment_time,
            self.items.c.item_id,
        ) < (
            last_shipment_time,
            last_item_id,
        ))
        .order_by(
            self.items.c.shipment_time.desc(),
            self.items.c.item_id.desc(),
        )
        .limit(limit)
    )
    with self.get_connection() as connection:
        result = connection.execute(s)
        return result.fetchall()

如果两个项目具有相同的shipment_time，则应该在比较中使用item_id打破平局。

显然 SQL 对此有支持 ()。但是，当我使用这个查询时，它似乎忽略了元组的第二个元素。

我正在为数据库使用 SQLite。

Answer 1

您需要在where条件中指定您使用的是元组：

from sqlalchemy import tuple_

def get_paginated_items(
        self,
        limit: int,
        last_shipment_time: int = MAX_INT,
        last_item_id: int = MAX_INT,
    s = (
        select([self.items])
        .where(tuple_(
            self.items.c.shipment_time,
            self.items.c.item_id,
        ) < tuple_(
            last_shipment_time,
            last_item_id,
        ))
        .order_by(
            self.items.c.shipment_time.desc(),
            self.items.c.item_id.desc(),
        )
        .limit(limit)
    )
    with self.get_connection() as connection:
        result = connection.execute(s)
        return result.fetchall()

SQLAlchemy 查询与多列元组比较

SQLAlchemy query with where with comparison on tuple of multiple columns

python

sqlite

sqlalchemy