To be honest with you I don't like dynamic sql because of quotation marks '' which are making whole code harder to read 🙂

So Instead of this I developed something like this:

where condition1 and (SomeDate >= CASE WHEN @StartDate is null THEN SomeDate ELSE @StartDate END or SomeDate is null)

and (SomeDate <= CASE WHEN @EndDate is null THEN SomeDate ELSE @EndDate END or SomeDate is null) and condition2