Python Sqlalchemy Order_By Datetime?
I'm Using Sqlalchemy to Store Some Objects with a Datetime Field: My_Date = Field(Datetime()) I'd Like to Run a Query to Retrieve the Most Recent Few Objects...
I'm using SqlAlchemy to store some objects with a DateTime field:
my_date = Field(DateTime())
I'd like to run a query to retrieve the most recent few objects (Entities with the my_date field that are the most recent).
I've tried the following:
entities = MyEntity.query.order_by(MyEntity.time).limit(3).all()
entities = MyEntity.query.order_by(-MyEntity.time).limit(3).all()
But these queries return the same objects in the same order. The SqlAlchemy documentation notes the use of the '-' to reverse the order, but I'm surely missing something here.
Can anyone help?
3 Answers
You can do it like this:
entities = MyEntity.query.order_by(desc(MyEntity.time)).limit(3).all()
You might need to:
from sqlalchemy import desc
Here's some documentation.
Another option is this:
stmt = select([users_table]).order_by(users_table.c.name.desc())
entities = MyEntity.query.order_by(MyEntity.my_date.desc()).limit(3).all()
should work.
You can use like this
from sqlalchemy import desc
db.session.query(MyEntity).order_by(desc(MyEntity.time))
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