mysql - 合并并用名称替换表 ID

Question

表员工:

+----+------------+
| id | firstname  |
+----+------------+
| 1  |   name1    | 
+----+------------+

表订单:

+----+--------+
| id |  eid   |
+----+--------+
|  1 |   2    |        
+----+--------+

可以通过一个查询得到这个结果吗？

+----+--------+
| id |  eid   |
+----+--------+
| 1  | name1  |        
+----+--------+

Answer 1

如果orders.eid的数据类型是int，则不能直接执行update。首先将其更改为 sting，然后执行此 UPDATE 语句，

UPDATE  orders a
        INNER JOIN employee b
            ON a.id = b.id
SET     a.eid = b.firstName