Of raw material "0169" class student id, name and the optional course gate number, average,
(beginner, want to ask you, thank you)

CodePudding user response:

Probably mean it

 SELECT student id, 
Name, 
COUNT (1) AS gate number, 
AVG (mark) AS average 
FROM the students watch 
The JOIN elective table 
Table ON students. Student id=elective courses table. Student id 
GROUP BY student id, 
The name;