Database: insurance_policies

Question: Who are the customers that had more than 1 policy? List the customer details and id.
SQL: 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

Question: What is the most popular payment method?
SQL: SELECT Payment_Method_Code FROM Payments GROUP BY Payment_Method_Code ORDER BY count(*) DESC LIMIT 1

Question: With which kind of payment method were the least number of payments processed?
SQL: SELECT Payment_Method_Code FROM Payments GROUP BY Payment_Method_Code ORDER BY count(*) ASC LIMIT 1

Question: Which kind of policy type was chosen by the most customers?
SQL: SELECT Policy_Type_Code FROM Customer_Policies GROUP BY Policy_Type_Code ORDER BY count(*) DESC LIMIT 1

Question: List the details of the customers who do not have any policies.
SQL: SELECT customer_details FROM Customers EXCEPT SELECT T1.customer_details FROM Customers AS T1 JOIN Customer_Policies AS T2 ON T1.customer_id  =  T2.customer_id