Mysql update problems

Mysql UPDATE problem UPDATE & nbsp; cg_disease_department & nbsp; AS & nbsp; a & nbsp; SET & nbsp;. department_id & nbsp ;=& nbsp; & nbsp; SELECT & nbsp; department_id & nbsp; FROM mysql update problems
UPDATE cg_disease_department AS a SET a. department_id =
SELECT department_id FROM cg_department AS B WHERE a. department_name = B. name

My requirement is to update the dimension mentid of Table B to the dimension mentid of Table a. The condition is a. department_name = B. name.

I shared this SQL question here:
------ Solution --------------------
The manual says:
You can also perform UPDATE operations on multiple tables. The table_references clause lists the tables contained in the Union. This syntax is described in section 13.2.7.1 "JOIN syntax. The following is an example:

UPDATE items, month SET items. price = month. price
WHERE items. id = month. id;
The preceding example shows the internal union using the comma operator, but the multiple-table UPDATE statement can use any types of union allowed in the SELECT statement, such as left join.

Note: you cannot use order by, LIMIT, or multiple-table UPDATE simultaneously.

So you should know where the problem is?