I\'m having a bit of a problem with using my sequence within a SELECT statement.
SELECT
SELECT c.cust_name, c.site, customer_id_seq.nextval
You cannot use sequences in queries with ORDER BY.
ORDER BY
Remove the ORDER BY or put in into a subquery:
SELECT q.*, customer_id_seq.nextval FROM ( SELECT c.cust_name, c.site FROM customer c WHERE c.customer_id IS NULL ORDER BY c.site_code ASC ) q