sql - 统计比赛参加人数

Question

我有这样的架构 http://sqlfiddle.com/#!17/30859/1 ，正如您在那个 SQL fiddle 中看到的那样，我有一个需要改进的查询，实际上我需要添加新列，这将给我每个锦标赛的参与者总数，我不确定我该怎么做，我试过了子选择但没有任何成功。在此先感谢您的帮助

Answer 1

SELECT t.id, t.name as tournamentName, m.name as creator, s.name as 
sponsorName,
(count * from member_tournament mt where mt.tournament_id=t.id) members
FROM tournament t 
LEFT JOIN member m ON m.id = t.member_id 
LEFT JOIN sponsor s ON s.id = t.sponsor_id