Mysql多个左连接在同一个表上

Question

我有一个包含两个字段的表，它引用了另一个表的ID。我需要从两个字段的另一个表中提取名称。

例如

 
Table1
worker1 = 2  (2 is key to other table)
worker2 = 4


Table2
ID NAME
1 Bill
2 Fred
3 John 
4 Paul

我需要获得$ worker1name = Fred和$ worker2name = Paul。

所以我会说：

SELECT xxx, NAME?, NAME? FROM Table1
LEFT JOIN Table2 AS p1 ON Table1.worker1 = Table2.ID
LEFT JOIN Table2 AS p2 ON Table1.worker2 = Table2.ID
WHERE ...

$table = mysql_query(...);
$rec = mysql_fetch_assoc($table);
$worker1name = $rec['???'];
$worker2name = $rec['???'];

我在最后两个语句中插入什么来获取这两个名称。或者更确切地说，我必须添加到SELECT中以指定我想要从表2中调用两个不同版本的NAME字段的方法吗？

Answer 1

您应该将字段别名如下：

SELECT
   xxx,
   p1.NAME as p1name,
   p2.NAME as p2name
FROM Table1
LEFT JOIN Table2 AS p1 ON Table1.worker1 = p1.ID
LEFT JOIN Table2 AS p2 ON Table1.worker2 = p2.ID
WHERE ...

Answer 2

SELECT xxx, p1.NAME AS p1Name, p2.NAME AS p2Name FROM Table1


$worker1name = $rec['p1Name'];
$worker2name = $rec['p2Name'];