SQL UPDATE引用MySQL中的同一个表的子查询

我试图用UPDATE更新表中一堆行的列值。 问题是我需要使用子查询来派生这个列的值，它依赖于同一个表。 这是查询：

UPDATE user_account student SET student.student_education_facility_id = ( SELECT teacher.education_facility_id FROM user_account teacher WHERE teacher.user_account_id = student.teacher_id AND teacher.user_type = 'ROLE_TEACHER' ) WHERE student.user_type = 'ROLE_STUDENT'; 

一般来说，如果老师和学生在两个不同的表中，MySQL不会抱怨。 但是因为它们都使用同一个表，所以mysql会发出这个错误：

错误1093（HY000）：您无法在FROM子句中指定目标表'student'进行更新

有什么办法可以强制MySQL做更新？ 我是100％正面的FROM子句不会因为行更新而受到影响。

如果没有，是否有另一种方式，我可以写这个更新SQL来实现相同的影响？

谢谢！

编辑：我想我得到它的工作：

 UPDATE user_account student LEFT JOIN user_account teacher ON teacher.user_account_id = student.teacher_id SET student.student_education_facility_id = teacher.education_facility_id WHERE student.user_type = 'ROLE_STUDENT'; 

Answer 1

一些对你的参考http://dev.mysql.com/doc/refman/5.0/en/update.html

 UPDATE user_account student INNER JOIN user_account teacher ON teacher.user_account_id = student.teacher_id AND teacher.user_type = 'ROLE_TEACHER' SET student.student_education_facility_id = teacher.education_facility_id 

Answer 2

具有更清晰的表名和列名的抽象示例：

 UPDATE tableName t1 INNER JOIN tableName t2 ON t2.ref_column = t1.ref_column SET t1.column_to_update = t2.column_desired_value 

正如@Nico所build议的那样

希望这可以帮助别人。

Answer 3

 UPDATE user_account SET (student_education_facility_id) = ( SELECT teacher.education_facility_id FROM user_account teacher WHERE teacher.user_account_id = teacher_id AND teacher.user_type = 'ROLE_TEACHER' ) WHERE user_type = 'ROLE_STUDENT' 

以上是示例更新查询…

您可以使用更新SQL语句编写子查询，您不需要为该表提供别名。 给子查询表提供别名。 我试过了，对我来说工作很好….

Answer 4

 UPDATE user_account student SET (student.student_education_facility_id) = ( SELECT teacher.education_facility_id FROM user_account teacher WHERE teacher.user_account_id = student.teacher_id AND teacher.user_type = 'ROLE_TEACHER' ) WHERE student.user_type = 'ROLE_STUDENT'; 

Answer 5

当我这样做时，我得到“错误：组function的无效使用”。

但是这个post： mysql查询更新字段为max（field）+ 1

显示了一个更加嵌套的子查询事物。

Answer 6

我需要这个SQL Server。 这里是：

 UPDATE user_account SET student_education_facility_id = cnt.education_facility_id from ( SELECT user_account_id,education_facility_id FROM user_account WHERE user_type = 'ROLE_TEACHER' ) as cnt WHERE user_account.user_type = 'ROLE_STUDENT' and cnt.user_account_id = user_account.teacher_id 

我认为它适用于其他关系数据库（请确认）。 我喜欢这个语法，因为它是可扩展的。

我需要的格式实际上是这样的：

 UPDATE table1 SET f1 = cnt.computed_column from ( SELECT id,computed_column --can be any complex subquery FROM table1 ) as cnt WHERE cnt.id = table1.id 

Answer 7

 UPDATE user_account student, ( SELECT teacher.education_facility_id as teacherid FROM user_account teacher WHERE teacher.user_account_id = student.teacher_id AND teacher.user_type = 'ROLE_TEACHER' ) teach SET student.student_education_facility_id= teach.teacherid WHERE student.user_type = 'ROLE_STUDENT';