CREATE TABLE Customer_Policies (Customer_id VARCHAR2)
CREATE TABLE Customers (customer_details VARCHAR2, customer_id VARCHAR2, Customer_id VARCHAR2)

Who are the customers that had more than 1 policy? List the customer details and id.
SELECT T1.customer_details, T1.Customer_id FROM Customers AS T1 JOIN Customer_Policies AS T2 ON T1.Customer_id = T2.Customer_id GROUP BY T1.Customer_id HAVING COUNT(*) > 1
SELECT "T1"."customer_details", "T1"."Customer_id" FROM "Customers" "T1" JOIN "Customer_Policies" "T2" ON "T1"."Customer_id" = "T2"."Customer_id" GROUP BY "T1"."Customer_id" HAVING COUNT(*) > 1