select
        round(sum(score) / count(rec_user),3) avg_score
from (
    select
        distinct rc_tb.rec_user,
        u_a_tb.score
    from 
            recommend_tb as rc_tb
    left join 
            user_action_tb as u_a_tb
    on 
            rc_tb.rec_user = u_a_tb.user_id
    where 
            rc_tb.rec_info_l = u_a_tb.hobby_l
)a