PHP mysql计算2列之间

I want to calculate how much percentage is positive and negative for voting. For instance, I have like 5 positive and 5 negative votes it should make it 50%, right?

How can i do that in a mysql/php query?

The columns are like this:

no yes yes no no no no yes yes yes

select id, 
       100 * sum(vote_column = 'yes') / count(vote_column) as percentage
from your_table
group by id