Hi.
I have an inheritance hierarchy on the form, C inherits B (with single
table inheritance), B inherits A (with joined table inheritance).
The next query works perfectly:
session.query(C)\
.join(C.related_objects)
.filter( ... ) # Unrelated filtering conditions
as the resulting SQL does the join between the tables for
A.__tablename__ and B.__tablename__, and filters B.__tablename__ using
the discriminator column in the WHERE.
However, I need to do this:
session.query(func.sum(RelatedTable.value))\
.select_from(C)\
.join(C.related_objects)\
.filter( ... )\ # Unrelated filtering conditions
.one()
While the select_from() still does correctly the A/B join, the filtering
condition is missing, so select_from(C) becomes the same as select_from(B).
I'm getting the right result using a explicit filter condition
"filter(C.discriminator == C_DISCRIMINATOR)", but I guess I'm missing
something.
Is this a kind of special case where some extra syntax is required? I
didn't find anything relevant in the docs, neither in inheritance nor
select_from() parts.
Thanks in advance.
Julio.
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