max(version_date) . group by item.id
On Monday, August 22, 2016 at 9:52:55 AM UTC+2, Encompass solutions wrote:
>
> Consider the following pseudo model.
>
> item
> ->name = "string"
>
> version
> ->item_id = item.id
> ->version_date = "datetime"
>
>
> While I can easily create a collectio
This document doesn't mention your method or using max()
http://web2py.com/books/default/chapter/29/06/the-database-abstraction-layer#sum-avg-min-max-and-len
Or I don't understand how you would do it.
Could you provide greater detail on how to build that query?
BR,
Jason
On Monday, August 22, 20
what you want is the latest version for each item_id . That is the row
having the greatest version_date if you divide your dataset for each
item_id.
that is what groupby item_id does. and what max(version_date) does too.
On Tuesday, August 23, 2016 at 11:05:52 AM UTC+2, Encompass solutions
Does this seem sensible? It seems to work with my initial tests.
latest_versions = db( (db.item.id == db.item_version.artifact_id) &
(db.item_version.id > 0)
).select(db.item.ALL,db.item_version.version_date.max(), groupby=db.item.id)
the .ma
On Wednesday, August 24, 2016 at 10:29:09 PM UTC-7, Encompass solutions
wrote:
>
> Does this seem sensible? It seems to work with my initial tests.
>
> latest_versions = db( (db.item.id == db.item_version.artifact_id) &
> (db.item_version.id > 0)
>
Grr, And now I can't get the db.item_version.ALL without Postgresql
panicking about not having the item in the group buy. How do I get the
fields in the result set? Do I need to place it in as a belongs or
something?
latest_versions = db( (db.item.id == db.item_version.artifact_id) &
I suppose your right, but I was a little thrown, by the:
max(variable_here)
That was mentioned was not the solution at all, I kept looking for ways to
use max as a function.
My issue now, is that the group by doesn't like me getting all the tables I
want in the return.
BR,
Jason Brower
On Thursd
you're thinking with a human mind instead of thinking on how a database
works... with sets of data.
How can you ask a database to return a single set grouped by something and
at the same time as for granular records???
When you use groupby, you can just ask for granular records of the columns
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