题解 | #按城市对客户排序,如果城市为空，则按国家排序#
请按城市对客户进行排序,如果城市为空，则按国家排序
https://www.nowcoder.com/practice/c1b1d5bd008b4797ab2ef53a3afc4aba
select
customer_id,
gender,
city,
country,
age,
latest_place_order_date
from
customers_info
order by
case
when city is not null then city
else country
end
