Retrieving sets with highest number of combined votes among objects - mysql

Question

I have three tables relevant to this problem - rankset, item, and vote. Rankset is essentially the category the item is placed in, such as "Favorite sport". Item is what's actually being voted on, such as "Baseball". Vote is the log of the vote itself. What I want to do is display the 25 most active ranksets on a page. Here's what the tables themselves look like:
CREATE TABLE IF NOT EXISTS `rankset` (
`id` INT NOT NULL AUTO_INCREMENT ,
`name` TEXT NOT NULL ,
PRIMARY KEY (`id`) )
ENGINE = InnoDB
CREATE TABLE IF NOT EXISTS `item` (
`id` BIGINT NOT NULL AUTO_INCREMENT ,
`name` VARCHAR(128) NOT NULL ,
`rankset` BIGINT NOT NULL ,
`image` VARCHAR(45) NULL ,
`description` VARCHAR(140) NULL ,
PRIMARY KEY (`id`) )
ENGINE = InnoDB
CREATE TABLE IF NOT EXISTS `mydb`.`vote` (
`id` BIGINT NOT NULL AUTO_INCREMENT ,
`value` TINYINT NOT NULL ,
`item` BIGINT NOT NULL ,
`user` BIGINT NOT NULL ,
PRIMARY KEY (`id`) )
ENGINE = InnoDB
This is what I've tried so far:
SELECT rankset.*, COALESCE(COUNT(vote.id), 0) AS votes
FROM rankset, item, vote
WHERE rankset.id = item.rankset
AND vote.item = item.id ORDER BY votes DESC LIMIT 25
For whatever reason, I seem to only be able to get the single most popular rankset with that. I've also tried this:
SELECT rankset.*, COALESCE(COUNT(vote.id), 0) AS votes
FROM rankset, vote, item
WHERE item.rankset = rankset.id
GROUP BY rankset ORDER BY votes DESC LIMIT 25
But that seems to ignore the "ORDER BY" part completely. What would be the correct way to go about this?
EDIT: Here's the fiddle: http://sqlfiddle.com/#!2/b57ac

Answer 1

Your queries are nearly right. In first one you should just add 'GROUP BY rankset'. Try that:
SELECT rankset.*, COALESCE(COUNT(vote.id), 0) AS votes
FROM rankset, item, vote
WHERE rankset.id = item.rankset
AND vote.item = item.id
GROUP by rankset.id
ORDER BY votes DESC
LIMIT 25;
Here's the fiddle: http://sqlfiddle.com/#!2/fe315/9.
UPDATE:
The case if some rankset doesn't have any votes:
SELECT rankset.*, COALESCE(COUNT(vote.id), 0) AS votes
FROM rankset, item
LEFT JOIN vote ON (vote.item = item.id)
WHERE rankset.id = item.rankset
GROUP by rankset.id
ORDER BY votes DESC
LIMIT 25;