select
    min(t3.score) min_score_over_avg
from
    (select
        t1.score,
        avg(t1.score) over(partition by t2.tag) avg_score
    from 
        exam_record t1
    left join
        examination_info t2
    on
        t1.exam_id = t2.exam_id
    where
        t2.tag = 'SQL'
        and t1.score is not null) t3
where
    t3.score >= t3.avg_score