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Changes between Initial Version and Version 11 of Ticket #28107

-              initial
+              v11
 {{{ qs.annotate(num_attachments=Count('attachments')) }}}
 The root cause appears to be that the relation between the model and attachments tables uses a unique field ''other than the main model's primary key'' (I know -- told you it was ugly - ArcSDE does not really support relations, except they implement attachments with this odd ball ** sigh **).
+The root cause appears to be that the relation between an unmanaged model (backed by a DB View) and attachments tables uses a unique field ''other than the main model's primary key'' (I know -- told you it was ugly - ArcSDE does not really support relations, except they implement attachments with this odd ball ** sigh **).
 The change in behaviour seems to manifest from #19259 (I believe django1.8 added all fields to the groupby clause).
 Since django now includes only the primary key in the groupby clause, postgresql won't do this aggregation across a relation that uses a non-pk field.
 I suspect there is a general issue here that aggregations on a related-table won't work in postgresql unless the relation is on the primary key field (so, yeah, basically this issue applies to almost no one, right...).
+UPDATE:  The root cause is actually that Postgresql treats Views differently than Tables w.r.t. what is required in the group by clause.
 Seems likely there is a better solution to this, but after a half-day of search / effort, I resorted to the following: