Query.apply_sum() does not work as expected from reading the documents

In reading the docs on Query.apply_sum(), the description was vague, and it did not explain it's behavior. This is best explained through examples.

Host.query().sum(Host.c.cpu_speed * Host.c.num_cpus)

In short, this is a goofy benchmark used in Smolt https://hosted.fedoraproject.org/projects/smolt/ which calculates a fairly useless but fun benchmark of the systems in the database. It generates the following SQL

SELECT sum(host.cpu_speed * host.num_cp_us) FROM host

Which is precisely the desired SQL. It was expected that apply_sum() could provide the same.

In testing it with apply_sum(), i received the following error:

Host.query().apply_sum(Host.c.num_cpus) Traceback (most recent call last): File "<console>", line 1, in <module> File "/usr/lib/python2.5/site-packages/sqlalchemy/orm/query.py", line 630, in getattr raise AttributeError(key) AttributeError: apply_sum

This leads me to two conclusions

A) apply_sum() is redundant and also broken, please remove, at least from the documentation. B) apply_sum() does something different, what is it?

At any rate, Query.sum() did work, and even worked with a "Criterion" although I'm not sure that's the right word at this point. I was pleasantly surprised, and this makes our code very very clean.

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