I have an existing table of customers. I want to add a NEW row for each customer based on ALL of the services our company offers.
Customer - ID
Freddy - 123
Customer - ID - Service
Freddy - 123 - Serv1
Freddy - 123 - Serv2
Freddy - 123 - Serv3
INSERT INTO Customers (Service)
VALUES ('Serv1'), ('Serv2'), ('Serv3')
You need some sort of
JOIN, in this case a
SELECT c.Customer, c.Id, v.s FROM Customers c CROSS JOIN (VALUES ('Serv1'), ('Serv2'), ('Serv3')) v(s);
However, it doesn't make sense to insert this into the original table. That table only has two columns, but you seem to want a third one.