postgresql7.3
select coalesce(sum(eg.weight),0) as total_weight
from evaluation_gradesi eg, acs_objects ao
where content_revision__is_live(eg.grade_id) = true
and ao.context_id = :package_id
and eg.item_id = ao.object_id
select coalesce(sum(eg.weight),0)
from evaluation_gradesx eg, acs_objects ao
where content_revision__is_live(eg.grade_id) = true
and eg.item_id = ao.object_id
and ao.context_id = :package_id