sorry to say

sorting will not give distinct values but will just sort the data depending on asceding[default]or desc.

group by will group the data depending upon the distinct values with in a column by which we are grouping

sorting mean puting the value in a particular order could by alhphabatic

gouping mean making a group of same type of values and displaying a single row for that group

example

select deptno sum(sal) from emp group by deptno order by 1;

first the query will select all deptno and sal then will make group of all deptno and make sum of the sal of that group then it will put the value in order of deptno