Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE loan (credit_score INTEGER, cust_id VARCHAR)
TABLE: CREATE TABLE customer (credit_score INTEGER, cust_id VARCHAR)

### Question ###
Find the average credit score of the customers who do not have any loan.

### Accurate SQL ###

SELECT AVG(credit_score) FROM customer WHERE NOT cust_id IN (SELECT cust_id FROM loan)