Question

Hio Guys, I have the following SQL query;

INSERT INTO ps_ext_mod (id_order,product_reference,id_customer,email)
SELECT d.id_order, d.product_reference, o.id_customer, c.email
FROM ps_orders o
INNER JOIN ps_order_detail d ON d.id_order = o.id_order
INNER JOIN ps_customer c ON c.id_customer = o.id_customer

What I need to happen is to check the table ps_ext_mod if id_order already exists with the value to be inserted. If it does, then dont insert it.

Answer 1

You can just join back to the table and look for where the join fails, i.e.:

INSERT INTO ps_ext_mod (id_order,product_reference,id_customer,email)
SELECT d.id_order, d.product_reference, o.id_customer, c.email
FROM ps_orders o
INNER JOIN ps_order_detail d ON d.id_order = o.id_order
INNER JOIN ps_customer c ON c.id_customer = o.id_customer
LEFT JOIN ps_ext_mod em ON em.id_order = d.id_order
WHERE em.id_order IS NULL