Often people use a dateadd/datediff combination to remove times, or to set to a base time.

SELECT DateAdd(Day, Datediff(Day,0, GetDate() -1), 0)

returns midnight of yesterday. That might be what you want. The -1 goes to yesterday. If I remove that, I get today.

SELECT DateAdd(Day, Datediff(Day,0, GetDate() ), 0)