I must have spent a good hour hammering at this before I got it right.
Maybe rephrase it a bit, but I think it's a good example...
Assume that you want all users returned, but want to outline specifically
those belonging to group A or B (with the others having their group set to
None) in one query.
Also assume that in your app, all users belong to only one group.
It can be done with the following:
left=db.auth_membership.on(db.auth_user.id==db.auth_membership.user_id),db.auth_group.on((db.auth_group.id==db.auth_membership.group_id)&db.auth_group.role.belongs(("Group
A","Group B")))
Users = db().select(db.auth_user.ALL, db.auth_group.ALL, left=left)
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