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Diego | 1 Jul 2012 21:42
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Query relationship in order

Hi,

Say I have two entities A and B, that have a many to many relationship between them.

Now I'd like to get all Bs from a given A, ordered by some attribute of B. Something like

select B from A order by B.attr desc

How do I express that query using the ORM?

Thanks in advance,
Diego

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Michael Bayer | 3 Jul 2012 23:50
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Re: Query relationship in order

this is approached using joins as described in the ORM tutorial at http://docs.sqlalchemy.org/en/rel_0_7/orm/tutorial.html#querying-with-joins .

If you'd like to present a specific A to Query without filtering for A rows, you can use with_parent(), see the last example in http://docs.sqlalchemy.org/en/rel_0_7/orm/tutorial.html#common-relationship-operators .





On Jul 1, 2012, at 3:42 PM, Diego wrote:

Hi,

Say I have two entities A and B, that have a many to many relationship between them.

Now I'd like to get all Bs from a given A, ordered by some attribute of B. Something like

select B from A order by B.attr desc

How do I express that query using the ORM?

Thanks in advance,
Diego

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