Using Analytic Functions AVG(Mark) OVER (PARTITION BY StudentID ORDER BY StudentID, Mark)
SQL>
SQL> CREATE TABLE SAT (
2 StudentID INT NOT NULL,
3 ExamID INT NOT NULL,
4 Mark INT,
5 IfPassed SMALLINT,
6 Comments VARCHAR(255),
7 CONSTRAINT PK_SAT PRIMARY KEY (StudentID, ExamID));
Table created.
SQL>
SQL>
SQL> INSERT INTO SAT (StudentID,ExamID,Mark,IfPassed,Comments) VALUES (1,1,55,1,'Satisfactory');
1 row created.
SQL> INSERT INTO SAT (StudentID,ExamID,Mark,IfPassed,Comments) VALUES (1,2,73,1,'Good result');
1 row created.
SQL> INSERT INTO SAT (StudentID,ExamID,Mark,IfPassed,Comments) VALUES (2,3,44,1,'Hard');
1 row created.
SQL> INSERT INTO SAT (StudentID,ExamID,Mark,IfPassed,Comments) VALUES (2,5,39,0,'Simple');
1 row created.
SQL> INSERT INTO SAT (StudentID,ExamID,Mark,IfPassed) VALUES (2,6,63,1);
1 row created.
SQL>
SQL>
SQL> SELECT StudentID, Mark, AVG(Mark) OVER
2 (PARTITION BY StudentID
3 ORDER BY StudentID, Mark) Running_Avg_by_Student
4 FROM SAT
5 ORDER BY StudentID, Mark;
STUDENTID MARK RUNNING_AVG_BY_STUDENT
---------- ---------- ----------------------
1 55 55
1 73 64
2 39 39
2 44 41.5
2 63 48.6666667
5 rows selected.
SQL>
SQL>
SQL> drop table SAT;
Table dropped.
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