So why is it possible do a query.group_by() but not a possible to specify the columns to select as execution of the query fails in postgresql because it is trying to select all the columns of table "Foo" in this instance.

Or is their some way of combining the sql.select() module with the query module?

_____

From: Michael Bayer [mailto:mike...@zzzcomputing.com] Sent: Friday, August 24, 2007 7:14 PM To: sqla...@googlegroups.com Subject: [sqlalchemy] Re: Generative group_by query specify columns

On Aug 24, 2007, at 10:43 AM, Curtis Scheer wrote:

What is the syntax to specify the columns in a generative query?

q = session.query(Foo)

q = q.group_by([foo_table.c.description])

for currow in q:

print currow

This query selects all the columns in the Foo table, wondering how to specify the columns to select.

query(Foo) will always select all columns that correspond to a "Foo" object. for individual columns, use a SQL expression instead of a Query, i.e. select([foo_table.c.cola, foo_table.c.colb]).group_by(...).where(...).<etc>() .