Question

Let’s say, for example, this is a quiz where the answers are already loaded into a database from different students. Inside of the table with various student entries containing various student’s answers there is a row “masterentry” with all of the correct answers.

What I would like to do is code a button that will pull the master row on click and compare every other row against it. Starting with the first row, every time the column matches the master entry 1 point is assigned to a declared integer. When the row has completely been read the integer is stored in a “totalpoints” column. Then it moves on to the next row of answers.

I hope this makes sense the way I worded it, if there is an easier way to go about it I am open to suggestions. I don’t really need any help establishing the connection to the sql database. Any help would be greatly appreciated, thanks in advance for anyone’s time. I can provide more details if it would be helpful.

Answer 1

Just a rough guess based on vague idea of schema. You would just call this query from .NET (preferably stored in stored procedure, passing in a @QuizID) unless you really want to do it less efficiently by looping after pulling all of the data to the client…

;WITH master AS (SELECT a1 = Answer1, a2 = Answer2, ...
  FROM dbo.Quiz
  WHERE QuizID = @QuizID
  AND Answer = 'masterentry'
)
SELECT a.StudentID,
    Score = CASE WHEN a.Answer1 = master.a1 THEN 1 ELSE 0 END
          + CASE WHEN a.Answer2 = master.a2 THEN 1 ELSE 0 END
          + ...
FROM dbo.Quiz AS a
CROSS JOIN master
WHERE a.QuizID = @QuizID
AND a.Answer <> 'masterentry' -- or a.StudentID IS NOT NULL?

There may be some shortcuts here based on the data types. E.g. if the quiz is true/false there are some little tricks you can do to reduce the ... part.