题解 | #判断其是否有过购买记录#
判断其是否有过购买记录
https://www.nowcoder.com/practice/5cddad8995974b0c915ab89961428ee0
select customer_id, case when latest_place_order_date is not null then 1 when latest_place_order_date is null then 0 end if_placed_order from customers_info
case句式
case when 条件1 then 执行1
when 条件2 then 执行2
else 执行3
end as 新列名
