SQL: Actualizar registros a partir de otra tabla...

[Sergestux]

Checa estos dos ejemplos

Increment the sales count of the salesperson who manages the account for Acme Corporation, using the FROM clause syntax:
UPDATE employees SET sales_count = sales_count + 1 FROM accounts
WHERE accounts.name = 'Acme Corporation'
AND employees.id = accounts.sales_person;


Perform the same operation, using a sub-select in the WHERE clause:
UPDATE employees SET sales_count = sales_count + 1 WHERE id =
(SELECT sales_person FROM accounts WHERE name = 'Acme Corporation');