mysql - MySQL GROUP BY 的问题

Question

我正在尝试构建一个 SQL 查询，该查询应该输出所有用户事件，而不是求和或其他任何内容，而只是执行的每个事件的完整列表。

我遇到的问题是，我似乎无法让 GROUP BY 工作，以便打印出每个用户的事件。

SQLFiddle = http://sqlfiddle.com/#!2/5dce6/2

最终，我将构建这个 JSON 对象:

users: [{
    userid: '1', 
    name: 'John',
    activities: [{
       activity_typeid: 6431,
       time: "2013-01-01 00:00:00",
       activity_weight: 20
      }, {
       activity_typeid: 6431,
       time: "2013-01-01 00:00:00",
       activity_weight: 20
    }]
}, {
    userid: '2', 
    name: Peter',
    activities: [{
       activity_typeid: 6431,
       time: "2013-01-01 00:00:00",
       activity_weight: 20
      }
    }]
}]    

SQL:

SELECT activity_typeid, userid, time, activity_weight, activityname
FROM activity_entries
WHERE competitionid = '52a99783c5d6f'

Answer 1

SELECT activity_typeid, userid, time, activity_weight, activityname
FROM activity_entries
WHERE competitionid = '52a99783c5d6f' AND userid = someuserid