IF Condition in an SQL query

Question

I'm a newbie to SQL Server. Please help me to write the following Logic in a query.

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

Answer 1

IF DATEPART(HOUR, GETDATE()) > 16
BEGIN
    -- SELECT statement
END
ELSE 
BEGIN
    -- SELECT statement
END

It does not have to be in a stored procedure.

Answer 2

select a.name, if(a.is_active='t','Active','Inactive') from mytable a