Question

I have a query which returns the total number of votes (COUNT()) and the sum (SUM()) of all votes. A single vote is stored as a -1 or a 1.

Now I get the following and want to know what the number of positive votes is:

• SUM: -2
• Total votes: 4

What is the formula to get the number of positive (and negative) votes?

In the example the outcome is: -1 + -1 + -1 + 1 (3 negative votes and 1 positive)

Answer 1

-x +y = sum
x + y = tot
=> 2y = sum + tot
=> y = (sum + tot)/2 ; x = tot - y

where y is the number of positive votes and x the negatives.