declare @votes_count int

select @votes_count = count(ID) from EventRating
where
    IDEvent in (31,32,33,34,35,36,37,38,57,39,40,120,41,42,43,44,45,46,122,121,47,123,48,124,50,51,125,63,55,66,52,58,53,59,62,54,60,56,61,67)
    and Rating != 0

select
    IDevent,
    e.[Name],
    (count(cast(er.ID as decimal)) / @votes_count) + (sum(cast(er.Rating as decimal)) / count(er.ID) / 5) as score
from EventRating as er
inner join Events as e on e.ID = er.IDEvent
where
    er.IDEvent in (31,32,33,34,35,36,37,38,57,39,40,120,41,42,43,44,45,46,122,121,47,123,48,124,50,51,125,63,55,66,52,58,53,59,62,54,60,56,61,67)
    and er.Rating != 0
group by er.IDEvent, e.Name
order by score desc