Re: [sqlalchemy] Dynamic order by clause

[Michael Bayer]

On Feb 13, 2014, at 6:21 PM, Tony Garcia <tnyr...@gmail.com> wrote:

> Hello,
> I'm new to SQLAlchemy and have searched high and low for a solution to my 
> problem so I'm hoping someone here can help. I have a query where I need to 
> apply the 'order by' clause dynamically (both the column and the direction). 
> So a 'static' version of my query would be:
> 
> studies = session.query(Study).options(
>                                      joinedload(Study.system),
>                                      joinedload(Study.site)).
>                                      filter(System.system_id=41).
>                                      order_by(Study.study_id.desc()).
>                                      all()
> 
> However the order can be asc or desc and it could be any column from the 3 
> tables. I found this post on Stackoverflow which helps with a dynamic sort 
> direction (asc, desc), but it doesn't help me with the dynamic column:
> 
> http://stackoverflow.com/questions/20904226/python-sqlalchemy-dynamic-order-by

“dynamic” attribute access in Python is using the getattr() builtin function:

def my_query(order_by_column):

   query = 
session.query(Study).filter(Study.system_id=41).order_by(getattr(Study, 
order_by_column))

that seems like what you’re asking, hope it helps.

signature.asc
Description: Message signed with OpenPGP using GPGMail