Question

I have a table with fields user_id and votes. The votes field is either 1 for an up vote, or 0 for down vote.

What I’d like to do is display the total up votes and total down votes in one query for a specific user.

I was thinking I could maybe use GROUP BY somehow to achieve this, but I don’t know if I can use it with a SUM function somehow?

Answer 1

GROUP BY would only be necessary if you wanted the vote count for multiple users; with a single user, one need only specify a WHERE clause:

SELECT SUM(votes=1) AS upvotes, SUM(votes=0) AS downvotes
FROM   my_table
WHERE  user_id = ?

As an aside, you might want to consider having downvotes stored as -1 (instead of 0) in order that the net vote count can easily be calculated as just SUM(votes).