how to create a team leaderboard with info from 4 tables? - mysql

Question

This is tricky, I have been tasked with creating an team leader board where individuals complete tasks for a score. The score is defined in the table "station" and every time a user completes a task- a post is created in the posts table with the id of the station and their RFID (radio frequency ID). There is a team table which defines the team name.
i need a way to get the sum of all the post scores (joined points from stations table) a teams members have participated in.
The result should be sorted be team score and look something like if we have 4 teams with 4 members who participated in 4 events- whats the total score for each team
Team name one (Teams.name) | score
Team name two (Teams.name) | score
Team name three (Teams.name) | score
The tables -
CREATE TABLE `posts` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`rfid` varchar(50) NOT NULL,
`station_id` int(11) NOT NULL,
`updated_at` datetime NOT NULL,
`created_at` datetime NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=11 ;
-- --------------------------------------------------------
Table structure for table stations
CREATE TABLE `stations` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`description` text NOT NULL,
`points` int(11) NOT NULL,
`logic` varchar(200) NOT NULL,
`created_at` datetime NOT NULL,
`updated_at` datetime NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1023 ;
-- --------------------------------------------------------
Table structure for table teams
CREATE TABLE `teams` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
`created_at` datetime NOT NULL,
`updated_at` datetime NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=7 ;
-- --------------------------------------------------------
Table structure for table users
CREATE TABLE `users` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`rfid` varchar(50) NOT NULL,
`first_name` varchar(50) NOT NULL,
`last_name` varchar(50) NOT NULL,
`team` int(11) NOT NULL,
`quiz_score` int(11) NOT NULL,
`created_at` datetime NOT NULL,
`updated_at` datetime NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=5 ;
I have created an query for an individual leaderboard-
SELECT users.first_name, users.last_name, posts.rfid, sum(stations.points) score
FROM posts
JOIN users ON posts.rfid = users.rfid
JOIN stations ON posts.station_id = stations.id
GROUP BY posts.rfid
ORDER BY score DESC LIMIT 0 , 100
this is what i have got so far for the team one
SELECT name, (SELECT sum(stations.points) score FROM posts
JOIN users ON posts.rfid = users.rfid
JOIN stations ON posts.station_id = stations.id
WHERE users.team = teams.id
GROUP BY posts.rfid) team_score FROM teams
//subquery returns more than one row
I think this might be the correct answer
SELECT name,
(SELECT sum(stations.points) score FROM posts
JOIN users ON posts.rfid = users.rfid
JOIN stations ON posts.station_id = stations.id
WHERE users.team = teams.id ) team_score
FROM teams