Here's what I ended up with.....if anyone else ever needs to do this.
select
(SQRT((sum((MyFieldName - (select convert(dec(10,2),avg(MyFieldName))From MyTableNameWhere MyWhereCriteria and abs(MyFieldName)>0))*(MyFieldName - (select convert(dec(10,2),avg(MyFieldName))From MyTableNameWhere MyWhereCriteria and abs(MyFieldName)>0)))) /(select count(MyFieldName)-1 from MyTableNamewhere MyWhereCriteria))) 'StDev'
from MyTableNameWHERE MyWhereCriteria
It matches exactly with what you get from excel or something like that.