Cheers...
Hm, still @ quite the n00b stage... got this far
Build.join(ExternalBuild).distinct().count()
But when I try
Build.join(ExternalBuild, ExternalBuild.build_id == Build.id)
It says:
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "<string>", line 1, in <lambda>
File
"c:\usr\python25\lib\site-packages\SQLAlchemy-0.5.2-py2.5.egg\sqlalchemy\util.py",
line 212, in go
return fn(*args, **kw)
File
"c:\usr\python25\lib\site-packages\SQLAlchemy-0.5.2-py2.5.egg\sqlalchemy\orm\query.py",
line 873, in join
return self.__join(props, outerjoin=False, create_aliases=aliased,
from_joinpoint=from_joinpoint)
File "<string>", line 1, in <lambda>
File
"c:\usr\python25\lib\site-packages\SQLAlchemy-0.5.2-py2.5.egg\sqlalchemy\orm\query.py",
line 52, in generate
fn(self, *args[1:], **kw)
File
"c:\usr\python25\lib\site-packages\SQLAlchemy-0.5.2-py2.5.egg\sqlalchemy\orm\query.py",
line 1071, in __join
clause = orm_join(clause, right_entity, onclause, isouter=outerjoin,
join_to_left=join_to_left)
File
"c:\usr\python25\lib\site-packages\SQLAlchemy-0.5.2-py2.5.egg\sqlalchemy\orm\util.py",
line 432, in join
return _ORMJoin(left, right, onclause, isouter, join_to_left)
File
"c:\usr\python25\lib\site-packages\SQLAlchemy-0.5.2-py2.5.egg\sqlalchemy\orm\util.py",
line 409, in __init__
expression.Join.__init__(self, left, right, onclause, isouter)
File
"c:\usr\python25\lib\site-packages\SQLAlchemy-0.5.2-py2.5.egg\sqlalchemy\sql\expression.py",
line 2479, in __init
__
self.right = _selectable(right).self_group()
File
"c:\usr\python25\lib\site-packages\SQLAlchemy-0.5.2-py2.5.egg\sqlalchemy\sql\expression.py",
line 968, in _select
able
raise exc.ArgumentError("Object %r is not a Selectable and does not
implement `__selectable__()`" % element)
ArgumentError: Object <sqlalchemy.sql.expression._BinaryExpression object at
0x01CB8B30> is not a Selectable and does no
t implement `__selectable__()`
----- Original Message ----
From: Michael Bayer <mike...@zzzcomputing.com>
To: sqlalchemy@googlegroups.com
Sent: Tuesday, February 3, 2009 12:58:03 AM
Subject: [sqlalchemy] Re: Using count with distinct?
use this:
http://www.sqlalchemy.org/docs/05/reference/sqlalchemy/expressions.html#sqlalchemy.sql.expression.distinct
On Feb 2, 2009, at 7:53 PM, Stuart Axon wrote:
>
> I've got a fairly simple query in postgres... any idea how I do this
> in sqlalchemy - I couldn't find any info about this
>
> select
> count(distinct device_id)
> from
> externalbuild
> join
> build
> on
> build.id = externalbuild.build_id
> where
> external_id = '1'
> and not
> is_known
>
>
> BTW, the recent work looks good - might even help me convert my
> other queries from sql... I thought this one
> was the simplest, but failed here too :-\
>
>
>
>
>
> >
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