问题与我LEFT JOIN，总结了它的结果，一个

Question

所以我有一个问题关于LEFT JOIN，该代码返回不同的值为totalPoints取决于用户是否得到了组与否。 （如果用户没有拿到团体或事件返回正确的值）

我只是想掌握如何得到LEFT JOIN flow_ 有 _vote ON flow_ 有 _vote.flow_id = flows.id每次工作。我之前做了一个解决方案之前有三个查询，一个获取组和事件规则，一个检查用户是否得到组或事件考虑安全性和一个获得流量...

而且我想我可以通过有两个查询来解决这个问题，一个可以获取组和事件规则，另外还可以检查用户是否获得了组和事件，然后根据用户获取流的应该有权访问它。

现在我得到在一个查询所需的每一个信息，然后检查与IF语句是否应打印或不...

所以，我的问题是，是否有可能得到SUM（flow_ 有 _vote.points）AS totalPoints以这种方式工作？你知道吗？

而且我有点古怪，是一种查询最好的方式来处理这个？在考虑性能时使用两个是否合理？

SELECT 
     flows.id AS flowId, 
     flows.security, 
     SUM(flow__has__vote.points) AS totalPoints, 
     users.id AS userId, 
     users.alias, 
     flows.event_id AS eventId, 
     events.group_id AS groupId, 
     events.membershipRules AS eMR, 
     groups.membershipRules AS gMR, 
     user__has__group.permission AS userHasGroup, 
     user__has__event.permission AS userHasEvent 
    FROM 
     users, 
     events LEFT JOIN user__has__event ON user__has__event.user_id = '.$userId.', 
     groups LEFT JOIN user__has__group ON user__has__group.user_id = '.$userId.', 
     flows LEFT JOIN flow__has__vote ON flow__has__vote.flow_id=flows.id 
    WHERE 
     flows.user_id = users.id AND 
     events.id = flows.event_id AND 
     groups.id = events.group_id AND 
     flows.id='.$flowId 

如果你想知道的SQL语句是干什么的，获得的流量（后），关于事件和组流量中的信息资料，检查到该组的用户访问和事件也让所有的票流...

这是表的样子......

FLOWS id,security,event_id,user_id 
USERS id, alias 
EVENTS id, name group_id, membershipRules 
GROUPS id, name, membershipRules 
USER__HAS__GROUP user_id,group_id,permission 
USER__HAS__EVENT user_id,event_id,permission 
FLOW__HAS__VOTE flow_id,user_id,points 

这是我想对...

+--------+----------+-------------+--------+--------+---------+---------+-----+-----+--------------+--------------+ 
| flowId | security | totalPoints | userId | alias | eventId | groupId | eMR | gMR | userHasGroup | userHasEvent | 
+--------+----------+-------------+--------+--------+---------+---------+-----+-----+--------------+--------------+ 
|  1 | 2  | 1337  | 5  | Pontus | 15  | 2  | 2 | 2 | 4   | 4   | 
+--------+----------+-------------+--------+--------+---------+---------+-----+-----+--------------+--------------+ 

0的结果

和一个例子......

+--------+----------+-------------+--------+--------+---------+---------+-----+-----+--------------+--------------+ 
| flowId | security | totalPoints | userId | alias | eventId | groupId | eMR | gMR | userHasGroup | userHasEvent | 
+--------+----------+-------------+--------+--------+---------+---------+-----+-----+--------------+--------------+ 
|  1 | 2  | 1337  | 6  | Kezia | 15  | 2  | 2 | 2 | null   | null   | 
+--------+----------+-------------+--------+--------+---------+---------+-----+-----+--------------+--------------+ 

享受生活〜庞

Answer 1

所以，基本上要点（恕我直言）是不包括表，你LEFT JOINed的WHERE子句中的条件，因为这使得LEFT JOIN表现得像INNER JOIN。

开始尝试这种查询（尽管我相信你会因为我不知道你想要的结果到底是什么，后面会详细讲解作出调整）：

SELECT 
     flows.id AS flowId, 
     flows.security, 
     SUM(flow__has__vote.points) AS totalPoints, 
     users.id AS userId, 
     users.alias, 
     flows.event_id AS eventId, 
     events.group_id AS groupId, 
     events.membershipRules AS eMR, 
     groups.membershipRules AS gMR, 
     user__has__group.permission AS userHasGroup, 
     user__has__event.permission AS userHasEvent 
FROM users, 
LEFT JOIN user__has__event 
    ON user__has__event.user_id = users.id, 
LEFT JOIN events 
    ON user__has__event.event_id = events.id 

LEFT JOIN user__has__group 
    ON user__has__group.user_id = users.id, 
LEFT JOIN groups 
    ON user__has__group.group_id = groups.id 
    AND groups.id = events.group_id 

LEFT JOIN flows 
    ON flows.user_id = users.id 
    AND events.id = flows.event_id 
    AND flows.id='.$flowId' 
LEFT JOIN flow__has__vote 
    ON flow__has__vote.flow_id = flows.id 

WHERE users.id = '.$userId.' 
GROUP BY users.id 

在这里，我LEFT JOINed一切交给用户，也由用户分组。我有一种感觉，你会想要添加列（flows.id ?, events.id？）

此外，您可能需要将LEFT JOINs中的一些设置为JOIN，因此，例如，您将只获得具有“流量”的用户。