描述

题解

生成序列表

with recursive t1 as
(select 1 as ids
union all
select ids+1 from t1
where ids<(select max(customer_id) from Customers))

用序列表与骨科表外连接筛选出剩余的id

select t1.ids
from t1 left join Customers as a on t1.ids=a.customer_id
where a.customer_name is null;

写一起

with recursive t1 as
(select 1 as ids
union all
select ids+1 from t1
where ids<(select max(customer_id) from Customers))
select t1.ids
from t1 left join Customers as a on t1.ids=a.customer_id
where a.customer_name is null;