mysql - MySQL - 使用来自同一表的子查询的值进行更新

Question

我有一个表'mytable'，它具有以下结构和示例数据。

+----+------------+--------------------+
| id | name       |   password         |
+----+------------+--------------------+
| 1  | Raj        |   somepwd          |
+----+------------+--------------------+
| 2  | Rao        |   abcdefg          |
+----+------------+--------------------+
| 3  | Uday       |                    |
+----+------------+--------------------+

我想用 Rao 的密码更新 Uday 的密码。谁能帮我用 MySQL 的更新查询来解决这个问题。

提前致谢。

Answer 1

UPDATE mytable 
set 
  password=(SELECT password FROM mytable WHERE name LIKE 'Rao') 
WHERE name LIKE 'Uday'

Answer 2

您需要使用此查询。

update mytable as t1,
(select id,`password` from mytable where name = 'Rao') as t2
set t1.password = t2.password
where t1.id = 3

Answer 3

update mytable set password = (select password from mytable where id=2) where id=3

或者你可以使用自我加入

update mytable t1 join mytable t2 on t1.id = 3 set t1.password = t2.password
where t2.id=2

注意：使用 id 代替其他列

Answer 4

我得到了解决方案，实际上最重要的解决方案给了我错误。

UPDATE mytable as aa, (SELECT password FROM mytable where id =2) as bb SET aa.password=bb.password where aa.id=3;