[英]MySQL Issue joining table with two columns against one
我有一個帶有id,first,last和identification列的聯系人表。 試圖讓名稱顯示在更大的連接中。 加入兩列時我無法顯示它。
表:
Inspections Id Order_Id Inspector_Id
聯系人ID First_Name Last_Name Orderer Inspector
這是我的SELECT:
$sql = " SELECT
Inspections.Id,
Inspections.Orderer_Id,
Inspections.Inspector_Id,
Contacts.Id
Contacts.First_Name AS OFirst,
Contacts.Last_Name AS OLast,
Contacts.First_Name AS IFirst,
Contacts.Last_Name AS ILast,
FROM Inspections
JOIN Contacts ON Inspections.Orderer_Id && Inspections.Inspector_Id=Contacts.Id
WHERE
Inspections.Id = " . $trigger . ";";
這只是最新的嘗試。 我已經嘗試了很多方法來加入它們,但我想我只是很難翻譯我在搜索時找到的代碼。 任何幫助將不勝感激!
如果Inspector和Orderer是同一個人,那么您當前的查詢只能起作用(一旦清除了語法錯誤),如果不是,則必須使用表別名連接兩次Contacts:
SELECT
Inspections.Id,
Inspections.Orderer_Id,
Inspections.Inspector_Id,
orderer.Id AS OId,
orderer.First_Name AS OFirst,
orderer.Last_Name AS OLast,
inspector.Id AS IId,
inspector.First_Name AS IFirst,
inspector.Last_Name AS ILast
FROM Inspections
JOIN Contacts AS orderer ON Inspections.Orderer_Id = orderer.Id
JOIN Contacts AS inspector ON Inspections.Inspector_Id = inspector.Id
WHERE Inspections.Id = xxxx
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