题解 | 商品销售总额分布

select
    case
        when pay_method = '' then 'error'
        else pay_method
    end as pay_method,
    count(*) as cnt
from
    user_client_log u
    join product_info p on u.product_id = p.product_id
where
    product_name = 'anta'
    and step = 'select'
    and pay_method is not null
group by
    pay_method
order by
    cnt desc;

首先合并两个表，再选出product_name = 'anta' and step = 'select' and pay_method is not null的行，再按照支付方式分类，并计算次数，对没有记录支付方式的用case when 显示error。