Difference between ORDER BY clause and GROUP BY clause in sql server.

here is the most comman difference of the order by clause or group by clause. ==>  the order by clause display the data in the sorted order of the given field ex:- select * from employee order by emp_name desc,emp_no asc; this query gives the output  in the ascending oredr of the emp_no and descending order of the emp_name. ==> while the group by clause is use to display the data in group of given field. ex;- select * from employee group by emp_name. this give the output data in the group of the emp_name.