I have a voting script which stores the post_id and the user_id in a table, to determine whether a particular user has already voted on a post and disallow them in the future.

To do that, I am doing the following 3 queries.

SELECT user_id, post_id from votes_table where postid=? AND user_id=?

If that returns no rows, then:

UPDATE post_table set votecount = votecount-1 where post_id = ?

Then

SELECT votecount from post where post_id=?

To display the new votecount on the web page

Any better way to do this? 3 queries are seriously slowing down the user's voting experience