Update Table If Condition from other table meet

hi, i would like to ask some help please. How to create an events for this scenario: their unique column is order_no

Table 1: customer
columns: customer name, status, order_no
Table 2: order
columns: order_no, status, date

if customer table coulmn status is COMPLETED

order table column status will be DELIVERED

both status column on tables has its own dropdowns.

i used this:

if($values["custome"] == "COMPLETED")

{

DB::Query("UPDATE order SET status ='DELIVERED' where order.order_no= customer.order_no");

}

but its not working. Help please.