I'm trying to know how the procedure done when using (group by) and how the result will be ordered without idintical data note even with these data the result still ambiguous , for example :
if we have a table has 2 columns (empno,ename)
empno 1 2 3 . ........... 26
ename a b c . ............ z
then execute --------------------->
select ename , empno
group by ename , empno
the result has to be to retrieve the table without changes but what happened illogical , so please help me to know the logic of (group by) .