問題與我LEFT JOIN，總結了它的結果，一個

Question

所以我有一個問題關於LEFT JOIN，該代碼返回不同的值爲totalPoints取決於用戶是否得到了組與否。 （如果用戶沒有拿到團體或事件返回正確的值）

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。我之前做了一個解決方案之前有三個查詢，一個獲取組和事件規則，一個檢查用戶是否得到組或事件考慮安全性和一個獲得流量...

而且我想我可以通過有兩個查詢來解決這個問題，一個可以獲取組和事件規則，另外還可以檢查用戶是否獲得了組和事件，然後根據用戶獲取流的應該有權訪問它。

現在我得到在一個查詢所需的每一個信息，然後檢查與IF語句是否應打印或不...

所以，我的問題是，是否有可能得到SUM（flow_ 有 _vote.points）AS totalPoints以這種方式工作？你知道嗎？

而且我有點古怪，是一種查詢最好的方式來處理這個？在考慮性能時使用兩個是否合理？

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語句是幹什麼的，獲得的流量（後），關於事件和組流量中的信息資料，檢查到該組的用戶訪問和事件也讓所有的票流...

這是表的樣子......

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 

這是我想對...

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

0的結果

和一個例子......

+--------+----------+-------------+--------+--------+---------+---------+-----+-----+--------------+--------------+ 
| 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〜龐

Answer 1

所以，基本上要點（恕我直言）是不包括表，你LEFT JOINed的WHERE子句中的條件，因爲這使得LEFT JOIN表現得像INNER JOIN。

開始嘗試這種查詢（儘管我相信你會因爲我不知道你想要的結果到底是什麼，後面會詳細講解作出調整）：

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 

在這裏，我LEFT JOINed一切交給用戶，也由用戶分組。我有一種感覺，你會想要添加列（flows.id ?, events.id？）

此外，您可能需要將LEFT JOINs中的一些設置爲JOIN，因此，例如，您將只獲得具有「流量」的用戶。