Your query is returning a date datatype, the gui interface (SSMS) is displaying as characters formatted as to the language of the login.

So

SELECT CONVERT(DATE,GETDATE()) AS CurrentDate;

and

SELECT CONVERT(varchar(10),GETDATE(),120) AS CurrentDate;

Both show 2014-08-29 in SSMS but the first is a date datatype and the second is varchar (string) and will be treated differently depending on what software is used.