How to get month and year from Date field in sqlalchemy?

Question

The result should be Date object

Since the day cannot be \'removed\', set it to say, 1st day of the month.

Leaving only Month, Year

Answer 1

You can use following constructs to filter the Date column using either year or month:

.filter(extract('year', Foo.Date) == 2012)
.filter(extract('month', Foo.Date) == 12)

And group_by is also possible:

.group_by(sqlalchemy.func.year(Foo.Date), sqlalchemy.func.month(Foo.Date))

Now I haven't tested it, but I assume that this might be slow because these queries result in full table scans, therefore I suggest you invest some time and learn how to use composite columns.

Answer 2

if you declare your schema like this,

schema.Column('created', types.TIMESTAMP(), default=now()),

the function now() is defined in the same module which can be like this

def now():
    now_date = datetime.datetime.now()
    return now_date.replace(day=1)

as per group_by requirement, here is a method mentioned.

you can modify hour and other field similarly.