where C.CalendarDate = getdate()
AND ((PC.DateRemoved is not null AND C.CalendarDate between PC.DateLive AND PC.Dateremoved)
OR
(PC.DateRemoved is null AND PC.DateLive < C.CalendarDate)
)
You're already in an IF statement of sorts with the Where clause. You simply need to build the boolean logic that evaluates to TRUE when a particular record should be selected.