SQL查询中的IF条件

Question

我是SQL Server的新手.请帮我在查询中编写以下逻辑.

If getnow() > today 4 PM
Then
    SELECT *
    FROM table
    WHERE MailDate is Tomorrow
Else
    SELECT *
    FROM table
    WHERE MailDate is Today

Answer 1

select *
from table
where DATEDIFF(day, GETDATE(), maildate) = case when
    DATEPART(hour, GETDATE()) >= 16 then 1 else 0
end