Question

我有以下查询按预期工作。

SELECT T.*, @curRank := @curRank + 1 AS rank
FROM ( SELECT e.guid, 
              e.name,
              (SELECT COUNT(ev.event_vote_id) 
               FROM event_vote ev 
               WHERE ev.event_uid = s.guid) AS votes
       FROM event e
    ) as T
CROSS JOIN  (SELECT @curRank := 0) r
ORDER BY votes DESC

它返回所有事件的guid，名称，投票数和排名。

但是我想通过使用以下内容链接 user_event 表来使其特定于某个用户：

JOIN user_event ON t.guid = ue.event_uid
WHERE ue.user_uid = 'abc123'

但是，我不确定将此放在哪里或是否这样。

我将以下查询作为开头，但它返回与预期相反的情况，即每个不属于该用户的事件。

SELECT t.* 
FROM user_event ue
JOIN ( SELECT e.guid,
              e.name,
              e.ownerId,
              e.thumbnailSrc,
              @curRank := @curRank + 1 AS rank,
              ( SELECT COUNT(ev.event_vote_id) 
                FROM event_vote ev 
                WHERE ev.event_uid = e.guid) AS votes
       FROM event e, (SELECT @curRank := 0) r
     ) AS t 
   ON t.guid = ue.event_uid
WHERE ue.user_uid = 'abc123'
ORDER BY rank ASC

预期结果

所有活动的清单：

guid | name | votes | rank

def    test2     2      1           (user1)
abc    test1     1      2           (user2)
ghi    test3     0      3           (user1)
jkl    test4     0      4           (user3)

查询应返回给用户1的内容（user1 guid为abc123）

guid | name | votes | rank

def    test2     2      1           
ghi    test3     0      3

Answer 1

如果您只想要来自某个特定用户的活动，请暂时忘记排名：

SELECT e.*, ue.*, ( ... ) as votes
FROM event e
JOIN user_event ue
  ON e.guid = ue.event_uid
WHERE ue.user_uid = 'abc123'

在结果上你可以做排名。

SELECT T.*, @curRank := @curRank + 1 AS rank
FROM ( ... previous query ... ) as T
CROSS JOIN  (SELECT @curRank := 0) r
ORDER BY votes DESC

修改

过滤您需要的单个用户创建另一个子查询。

计算投票

计算排名

过滤用户

所以查询变为：

SELECT * FROM ( SELECT T.*, @curRank := @curRank + 1 AS rank FROM ( SELECT e.*, ue.*, ( ... ) as votes FROM event e JOIN user_event ue ON e.guid = ue.event_uid ) as T CROSS JOIN (SELECT @curRank := 0) r ORDER BY votes DESC ) as ranked_result WHERE ranked_result.user_uid = 'abc123'

MySQL获取特定用户的结果

1 个答案: