When using "echo='debug'" I get the following:
In [22]: session.query(func.sum(Event.cycle)).scalar()
2014-11-12 08:14:35,697 INFO sqlalchemy.engine.base.Engine SELECT
sum(metrics_event.cycle) AS sum_1
FROM metrics_event
SELECT sum(metrics_event.cycle) AS sum_1
FROM metrics_event
2014-11-12 08:14:35,697 INFO sqlalchemy.engine.base.Engine ()
()
2014-11-12 08:14:35,698 DEBUG sqlalchemy.engine.base.Engine Col ('sum_1',)
Col ('sum_1',)
2014-11-12 08:14:35,698 DEBUG sqlalchemy.engine.base.Engine Row
(Decimal('50'),)
Row (Decimal('50'),)
Out[22]: Decimal('50')
It seems like mysql returns a Decimal object.
Moreover, I thought that I can use
session.query(type_coerce(func.sum(Event.amount / Event.cycle),
Float)).scalar()
for more complex aggregates but this doesn't work. Seems like I have to
manually convert values in python.
Thanks for your help.
On Tuesday, November 11, 2014 7:18:13 PM UTC+1, Michael Bayer wrote:
>
> The MySQL console can’t show you this because “Decimal” is a Python type.
> the way to see what is going on is to test with the MySQLdb driver
> directly, though in this case it’s easy enough to see it also with
> “echo=‘debug’”.
>
>
> On Nov 11, 2014, at 1:09 PM, Thomas Wanschik <[email protected]
> <javascript:>> wrote:
>
> Thanks for your answer.
>
> I did the exact same raw sql query (got the query string via echo=True)
> and it seems like mysql returned an integer (console print looked like a
> integer). So I concluded it has to be converted somewhere on the way
> through sqlalchemy.
>
>
> On Tuesday, November 11, 2014 6:25:44 PM UTC+1, Thomas Wanschik wrote:
>>
>> Hi,
>> the query
>>
>> session.query(func.sum(MyModel.amount)).scalar()
>>
>> with
>>
>> MyModel.amount = Column(SmallInteger, nullable=False)
>>
>> returns a Decimal instead of an integer when using mysql with the default
>> driver (as well as with the cymysql driver).
>>
>> How can I get this query to return an integer? And why can't it return an
>> integer automatically?
>>
>> Thanks in advance
>>
>
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