MySQL: Update all rows in a table matching results of another query

Question

I\'ve written a query returning rows associating Customers and Salespeoeple.

Note that the query joins several database tables. And note that not all c

Answer 1

Assuming your first table is named customers and those customers without a salesperson have an s_id of NULL

UPDATE invoices JOIN customers USING (c_id)
SET invoices.s_id = customers.s_id, invoices.s_name = customers.s_name
WHERE customers.s_id IS NOT NULL;

I suggest testing in development or running a SELECT query using the JOIN above first to ensure the results.