Use left JOIN and where statement when MySQL update

updatewe sometimes need to use the correlation table when using the statement left join , and here are the correct actions:
Effect to update the field of the order id finish_at freports table with fields of the specified table as the data of the created_at

UPDATE ordersLEFT JOIN  freportsON freports.order_id = orders.idset orders.finish_at = freports.created_atwhere orders.id in(1,2,3)



MySQL Export csv:
SELECT * FROM table to outfile '/users/k/desktop/task.csv ' fields terminated by ', ';

CSV import MySQL:

Load data local infile '/users/k/desktop/task.csv ' into table t_name

Fields terminated by ', '

(COL1,COL2,COL3);

Use left JOIN and where statement when MySQL update