How do I get the max value of the sum of rows using case

Question

I have a result portal where results are entered based on individual subject per term. I need to get the class highest score, average score, and minimum score per subject from the sum of three terms ( 1 academic year)

My code gets each of the subjects per term for each student but I need to get the highest, average, and lowest score after adding the three terms for each subject

My Query

SELECT results.subjects,
    MAX(CASE WHEN results.term = 'First' THEN results.examTotal END) 'First'
    ,MAX(CASE WHEN results.term = 'Second' THEN results.examTotal END) 'Second'
    ,MAX(CASE WHEN results.term = 'Third' THEN results.examTotal END) 'Third'
FROM results 
WHERE studId = '".$RegNo."' 
GROUP BY   results.subjects
ORDER BY results.subjects ASC

I expect to have a table

+-----+-------+--------+-----+----------+---------+---------+-------+
+Sub  + First + Second +Third+(Total/3) + Highest + Average + Lowest+
+-----+-------+--------+-----+----------+---------+---------+-------+
+ Eng +  79   +  80    +  67 +  75.33   +   80    +  60     +  45   +
+-----+-------+--------+-----+----------+---------+---------+-------+
+Maths+   60  +  77    + 73  +   70     +   90    +  60     +  40   +
+-----+-------+--------+-----+----------+---------+---------+-------+

Answer 1

You can get all the columns you need with your query, except (Total/3) for which is better to use an outer query to calculate it:

SELECT
  t.subjects, t.First, t.Second, t.Third,
  round((t.First + t.Second + t.Third) / 3.0, 1) `(Total/3)`,
  t.Highest, t.Average, t.Lowest
FROM (
    SELECT 
      subjects,
      MAX(CASE WHEN term = 'First' THEN examTotal END) First,
      MAX(CASE WHEN term = 'Second' THEN examTotal END) Second,
      MAX(CASE WHEN term = 'Third' THEN examTotal END) Third,
      MAX(examTotal) Highest, 
      MIN(examTotal) Lowest,
      AVG(examTotal) Average
    FROM results 
    WHERE studId = '".$RegNo."' 
    GROUP BY subjects
) t
ORDER BY t.subjects ASC