Change DateTime format
If you are looking for a particular string formatting of a datetime data type value then you need to work with the convert() function with a particular style.  In this case, you are looking for the style with a value of 110 (resulting in the format of mm-dd-yyyy):

select convert(char(10), getdate(), 110);


(Note: I use getdate() just to generate a datetime value, in which case you would just reference your datetime column) My output is this:

06-08-2014