將兩列與另一個表的相同字段連接起來

Question

我對 mysql 查詢有一個問題，從用戶表中獲取發送者和接收者的名稱

我有以下user_match_list表的結構

這是users表

我想將 senderId 與用戶表一起加入，並獲得 firstname + lastname 作為 senderName 與 receiverId 相同，並將 name 作為 receiverName 請指導我謝謝

Answer 1

聽起來你想要兩個join ：

select uml.*,
       concat(us.firstname, ' ', us.lastname) as sendername,
       concat(ur.firstname, ' ', ur.lastname) as receivername,
from user_match_list uml join
     users us
     on uml.sendid = us.id join
     users ur
     on uml.receiverid = ur.id;

Answer 2

您應該使用兩個連接：

SELECT us.firstName + ' ' + us.LastName,
       us2.firstName + ' ' + us2.LastName
FROM dbo.user_match_list AS um
INNER JOIN dbo.Users AS us ON um.senderId = us.Id
INNER JOIN dbo.Users AS us2 ON uml.receiverId = us2.Id