select
    case
        when a.pay_method = '' then 'error'
        else pay_method
    end as py,
    count(a.pay_method) as cnt
from
    user_client_log a
    left join product_info b using (product_id)
where
   a.step ='select'
    and b.product_name = 'anta'
group by
    a.pay_method
order by
    cnt desc