with
t1 as(
    select
        merchant_id,
        merchant_name,
        round(sum(sale_amount)/2,2) as total_sales_amount,
        round(sum(refund_amount)/4,2) as total_refund_amount,
        round(avg(satisfaction_score),2) as average_satisfaction_score
    from
        merchants_underline
        left join sales_underline using(merchant_id)
        left join refunds_underline using(merchant_id)
        left join satisfaction_underline using(merchant_id)
    group by
        merchant_id,
        merchant_name
)

select * from t1