smart_grid = SQLFORM.smartgrid(db.child,
left = (db.parent.on(db.child.parent_id),
# keywords = (db.parent.field_bla == some_value),
# constraints = {'parent': (db.parent.field_bla == some_value)},
...other settings...) smart_grid = SQLFORM.smartgrid(db.child,
left = (db.parent.on(db.child.parent_id & (db.parent.field_bla == some_value)),
...other settings...)