Mysql查询：连接

我有以下表格：

传输表：

ID | storagefrom | storageto 
1  | 2           | 3

存储表：

ID | Name
2  | Kitchen
3  | Main

我希望得到以下结果：

Storage1 | Storage2 
Kitchen   | Main

这是我的疑问：

SELECT storages.name as Storage1, storages.name as Storage2
FROM transfers 
LEFT JOIN storages ON storages.id = transfers.storagefrom
LEFT JOIN storages ON storages.id = transfers.storageto

---

有什么提示吗？

只需将条件聚合与

大小写表达式和1
连接一起使用即可：

SELECT t.id,
       MAX(CASE WHEN s.id = t.storagefrom THEN s.name END) as storage_1,
       MAX(CASE WHEN s.id = t.storageto THEN s.name END) as storage_2
FROM transfer t
LEFT JOIN storages s 
 ON(s.id IN(t.storagefrom,t.storageto))
GROUP BY t.id

如果它只有一条记录，而您不关心
transfer.id
，请将其从选择列表中删除，并删除
GROUP BY
子句。
只需为您的表添加别名即可

SELECT s1.name as Storage1, s2.name as Storage2
FROM transfers 
LEFT JOIN storages AS s1 ON s1.id = transfers.storagefrom
LEFT JOIN storages AS s2 ON s2.id = transfers.storageto

试一试

参考：

也许这会对你有所帮助：
SELECT T.ID,
       S1.Name Storage1,
       S2.name Storage2 
FROM transfers T
LEFT JOIN storages S1 ON S1.ID = T.storagefrom
LEFT JOIN storages S2 ON S2.ID = T.storageto