This is useful when you want to group records by date but your datetime column has a time value also.  This code converts your date to a varchar in a specified format.

--101 is "mm/dd/yyyy"

SELECT CONVERT(varchar,DateField,101)

-- 1 is "mm//dd/yy"

SELECT CONVERT(varchar,DateField,1)

-- 108 is "hh:mm:ss"

SELECT CONVERT(varchar,DateField,1)

-- An example query

Select convert(varchar,CallDateTime ,101), count(*)

FROM [DBName].[dbo].[TableName]

where

CallDateTime between '04/21/2006' and '05/21/2006'

group by convert(varchar,CallDateTime ,101)