使用来自另一个表的所有数据更新MySQL中的表

Question

I have 3 tables: ak_class, ak_objects, ak_class_object ak_class:

class_id | class_description | class_name |
1        | some description  | some name  |
2        | some description  | some name  |
3        | some description  | some name  | 

ak_objects: 
object_id | object_description | object_name |
1         | some description   | some name   |
2         | some description   | some name   |
3         | some description   | some name   | 

ak_class_object: 
class_object_id | class_id | object_id  |
1               | 1        | 1          |
2               | 2        | 2          |
3               | 3        | 3          | 

I need to fill in the ak_class_object with a class_id from ak_class table and object_id from ak_objects table.

The question is how can I update (I need to update as there is some wrong data currently) the class_id from the ak_class table with all the ids? I was thinking of using it with JOIN ut I don't know which id to use to Join them as class_id is only to be updated

UPD: I was trying to do it like this, but it didn't work:

DELIMITER $$
DROP PROCEDURE class_object_1$$
CREATE PROCEDURE class_object_1()
BEGIN
DECLARE i INT DEFAULT 0;
WHILE (i < 250000) DO
UPDATE ak_class_object 
SET class_id = SELECT DISTINCT class_id from ak_class, object_id = SELECT DISTINCT class_id from ak_objects;
SET i = i + 1;
END WHILE;
END$$

Answer 1

I am writing the generic syntax, change the table names and column name as per your requirements.

update table1 inner join table2
on table1.id = table2.fk_id
set table1.column = table1.columnUpdated