Steve Zatz wrote: > I realize this is actually an SQL question but I haven't been able to > figure out the answer. > > In a simple self-referential table, the following produces all the > Nodes that are parents to some child node(s): > > node_table_alias = node_table.alias() > parents = session.query(Node).filter(Node.id == node_table_alias.c.parent_id) > > I can't figure out the analogous query that produces all the Nodes > that are not parents to another node. It is clear that: > > non_parents = session.query(Node).filter(Node.id != > node_table_alias.c.parent_id) > > doesn't work but I can't figure out what the right query is. Any help > would be appreciated.
another option is: .query(Node).filter(not_(Node.id.in_(select([Node.parent_id])))) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
