我有一个测试记录数据库,其中一列test_time"定义为日期时间.我想查询有多少个不同的日期,因为我想根据日期将测试结果转储到 csv.我现在有以下内容:
I have a database of test records with one column 'test_time' defined as datetime. I want to query how many distinct dates there are as I want to dump test results to csv according to dates. I now have the following:
distinct_dates = list(session.query(Test_Table.test_time).distinct())但这给了我一个日期时间而不是日期的列表.当然我可以在 Python 中转换它,但是当我使用 sqlite 时.我做了这个SELECT DISTINCT DATE(test_time) FROM Test_Table.我无法想出 sqlalchemy 中的等价物.
But this gives me a list of datetime not date. Certainly I can convert it in Python but when I am using sqlite. I did this SELECT DISTINCT DATE(test_time) FROM Test_Table. I cannot come up with the equivalent in sqlalchemy.
推荐答案那将是使用 cast() 表达式:
That would be by using the cast() expression:
from sqlalchemy import cast, Date distinct_dates = session.query(cast(Test_Table.test_time, Date)).distinct().all()或快捷方法:
distinct_dates = session.query(Test_Table.test_time.cast(Date)).distinct().all()如果使用 SQLite,试一试:
and if using SQLite, give this a shot:
distinct_dates = session.query(func.DATE(Test_Table.test_time)).distinct().all()更多推荐
将选定的日期时间转换为 sqlalchemy 中的日期
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