Write the following query with and without the GROUP BY clause: List all students with their corresponding average grade.

Consider the following ODL de?nitions:

class Person : Object

          ( extent PersonExt ):PERSISTENT;

{

     attribute String Name;

     ... ... ...

}

class Student extends Person

          ( extent StudentExt ):PERSISTENT;

{

    attribute Integer Id;

    attribute Set Transcript;

    ... ... ...

}

struct TranscriptRecord {

       String CrsCode;

       float Grade;

       String Semester;

}

SELECT    S.Name, avg(flatten(S.Transcript).Grade)

FROM     StudentExt S

SELECT   S.Name, avg(T.Grade)

FROM      StudentExt S, S.Transcript T

GROUP BY S

The second query just complicates things — all for the sake of being able to use GROUP BY.