用其他表值更新表

Question

I have 2 tables department_referance and department which has code in department_referance is equal to department_string_id in department tables.

department_referance //table
id code   sl_flag
    DD01  1 

department //table
department_id department_string_id  sl_flag
               DD01

I want to fetch sl_flag value from department_referance and update the value in department table's sl_flag.

update sl_flag='(SELECT a.sl_flag FROM department_referance a inner JOIN department b on a.code=b.department_string_id)'

Answer 1

You can update it by joining( JOIN ) both the tables.

Query

update `department ` t1
join `department_referance ` t2
on t1.`code` = t2.`department_string_id`
set t1.`sl_flag` = t2.`sl_flag`;

Answer 2

you can use this query

UPDATE department d 
join department_referance 
dr on dr.code = d.department_string_id 
set d.sl_flag = dr.sl_flag