CREATE TABLE claim_headers (claim_header_id NUMBER, claim_status_code CLOB, claim_type_code CLOB, policy_id NUMBER, date_of_claim TIME, date_of_settlement TIME, amount_claimed NUMBER, amount_piad NUMBER)
CREATE TABLE staff (staff_id NUMBER, staff_details CLOB)
CREATE TABLE policies (policy_id NUMBER, customer_id NUMBER, policy_type_code CLOB, start_date TIME, end_date TIME)
CREATE TABLE claims_documents (claim_id NUMBER, document_type_code CLOB, created_by_staff_id NUMBER, created_date NUMBER)
CREATE TABLE claims_processing (claim_processing_id NUMBER, claim_id NUMBER, claim_outcome_code CLOB, claim_stage_id NUMBER, staff_id NUMBER)
CREATE TABLE customers (customer_id NUMBER, customer_details CLOB)
CREATE TABLE claims_processing_stages (claim_stage_id NUMBER, next_claim_stage_id NUMBER, claim_status_name CLOB, claim_status_description CLOB)

Which customer have the most policies? Give me the customer details.
SELECT t2.customer_details FROM policies AS t1 JOIN customers AS t2 ON t1.customer_id = t2.customer_id GROUP BY t2.customer_details ORDER BY COUNT(*) DESC LIMIT 1
SELECT "t2"."customer_details" FROM "policies" "t1" JOIN "customers" "t2" ON "t1"."customer_id" = "t2"."customer_id" GROUP BY "t2"."customer_details" ORDER BY COUNT(*) DESC FETCH FIRST 1 ROWS ONLY