SQL查询 - 某种选择不同？

Question

假设我有一个特定日子进来的客户记录,例如:

Cs  day
--  ---
01  Tue
02  Tue
03  Wed
01  Wed
04  Thu
02  Thu

我需要一个只返回周二和周三的客户的#s的查询.在这种情况下,只有Cs#01.

Answer 1

select distinct c1.Cs
from Customers c1 
inner join Customers c2 on c2.Cs=c1.Cs
where c2.day='Tue' and c1.day='Wed'