Question

To make a big sql structure simple: I am having next structure:

id    level    answercorrect    points
1     1        0                0
2     1        1                60
3     1        1                80
4     1        1                77
5     1        1                92
6     1        0                0
7     2        0                0
8     2        0                0
9     2        0                0
10    2        1                80
11    2        0                0
12    2        0                0

I now want to display two things:

1) how many levels were completed (this is min. half of the questions correct)

2) the level where you scored the most points.

Now I can go and manually do a query for each level, then compare them and then output them.

SELECT (*) FROM QUESTIONS WHERE LEVEL = level AND ANSWERCORRECT = 1

But Is there a way to do this quicker? It just seems like a to big bunch of code to accomplish that on my way..?

Answer 1

This will show you each level, with a count of answers, and a count of correct answers.

select level, 
    count(*) as totalquestions, 
    sum (answercorrect) as correctanswers,
    sum (points) as totalpoints
from yourtable
group by level
having sum (answercorrect) >= (count(*)/2)
order by sum (points) desc

Or

select level,  
    count(*) as totalquestions,  
    sum (answercorrect) as correctanswers, 
    sum (points) as totalpoints,
    case when sum (answercorrect) >= (count(*)/2) then 1 else 0 end as completed
from yourtable 
group by level 
order by sum (points) desc 

It seems superfluous to store points and correctness, if points = 0 implies incorrect and points>0 implies correct?