如何從三個表中獲取價值？

Question

我有三個表像這樣：

-drivingtime 
    +id 
    +starttime 
    +stoptime 
-fuel 
    +id 
    +timestamp 
    +fuellevel 
-addingfuel 
    +id 
    +timestamp 
    +fueladding 

，我預計將顯示開始時間，停止時間，fuellevel（在開始時間），fuellevel（在停止時間），fueladding在同一屏幕上。那我到底需要做什麼？我搜索谷歌的解決方案，但其他問題是完全不同的。

我想：

SELECT startTime and stopTime 
from tblDrivingTime d 
left join tblFuel f on d.startTime = f.timestamp 
left join tblFuel f on d.stopTime = f.timestamp 
left join tblDoXang x on d.startTime < x.timestamp < d.stopTime 

Answer 1

這裏是返回你正在尋找的結果的查詢：

SELECT DT.starttime 
    ,DT.stoptime 
    ,FB.fuellevel AS `startfuellevel` 
    ,FE.fuellevel AS `stopfuellevel` 
    ,(SELECT COUNT(AF.id) 
    FROM addingfuel AF 
    WHERE AF.timestamp BETWEEN DT.starttime AND DT.stoptime) AS `nbaddingevents 
FROM drivingtime DT 
INNER JOIN fuel FB ON FB.timestamp = DT.starttime 
INNER JOIN fuel FE ON FE.timestamp = DT.stoptime 

希望這會幫助你。