Question

我有这个查询，试图查找给定日期和状态的记录：

ld=LunchDay.query.filter(and_(func.DATE(LunchDay.timestamp == datetime.date.today()), LunchDay.status==1))

模型：

class LunchDay(db.Model):
    __tablename__ = 'lunch_day'

    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    user = relationship("User", foreign_keys=[user_id])
    timestamp = db.Column(db.DateTime, index=True, default=datetime.today())
    status = db.Column(db.Integer)

它运行并且没有引发错误，但似乎不考虑日期。它将在数据库的DateTimeField中找到日期为昨天的条目：

2018-11-13 00:00:00.000000

这是昨天的日期，但是它只是根据状态来选择它，就像将其视为“或”一样。我使用的导入是：

from sqlalchemy import func, and_

Answer 1

打印出查询所生成的实际sql，以查看发生了什么。例如：

ld=LunchDay.query.filter(and_(func.DATE(LunchDay.timestamp == datetime.date.today()), LunchDay.status==1))
print(ld)

打印：

SELECT lunch_day.id AS lunch_day_id, lunch_day.timestamp AS lunch_day_timestamp, lunch_day.status AS lunch_day_status
FROM lunch_day
WHERE DATE(lunch_day.timestamp = %(timestamp_1)s) AND lunch_day.status = %(status_1)s

您可以看到lunch_day.timestamp和参数timestamp_1的相等性正在传递给DATE函数。

在您的sqlalchemy查询中func.DATE(LunchDay.timestamp == datetime.date.today())实际上很容易看到。我假设您想将LunchDay.timestamp转换为日期，然后然后将其与应该为datetime.date.today()的{{1}}进行比较。

db.func.DATE(LunchDay.timestamp) == date.today()

打印：

print(LunchDay.query.filter(and_(func.DATE(LunchDay.timestamp) == datetime.date.today(), LunchDay.status == 1)))

要注意的另一件事是，传递到SELECT lunch_day.id AS lunch_day_id, lunch_day.timestamp AS lunch_day_timestamp, lunch_day.status AS lunch_day_status FROM lunch_day WHERE DATE(lunch_day.timestamp) = %(DATE_1)s AND lunch_day.status = %(status_1)s的多个语句会自动被视为filter()，因此您可以通过删除以下内容来简化查询：

and_()

sqlalchemy flask忽略过滤器查询中的and_和func.DATE

1 个答案: