-- Database schema
| Addresses : address_id [ INT ] primary_key , address_details [ TEXT ] | Staff : staff_id [ INT ] primary_key , staff_gender [ TEXT ] , staff_name [ TEXT ] | Suppliers : supplier_id [ INT ] primary_key , supplier_name [ TEXT ] , supplier_phone [ TEXT ] | Department_Store_Chain : dept_store_chain_id [ INT ] primary_key , dept_store_chain_name [ TEXT ] | Customers : customer_id [ INT ] primary_key , payment_method_code [ TEXT ] , customer_code [ TEXT ] , customer_name [ TEXT ] , customer_address [ TEXT ] , customer_phone [ TEXT ] , customer_email [ TEXT ] | Products : product_id [ INT ] primary_key , product_type_code [ TEXT ] , product_name [ TEXT ] , product_price [ INT ] | Supplier_Addresses : supplier_id [ INT ] primary_key Supplier_Addresses.supplier_id = Suppliers.supplier_id , address_id [ INT ] Supplier_Addresses.address_id = Addresses.address_id , date_from [ TEXT ] , date_to [ TEXT ] | Customer_Addresses : customer_id [ INT ] primary_key Customer_Addresses.customer_id = Customers.customer_id , address_id [ INT ] Customer_Addresses.address_id = Addresses.address_id , date_from [ TEXT ] , date_to [ TEXT ] | Customer_Orders : order_id [ INT ] primary_key , customer_id [ INT ] Customer_Orders.customer_id = Customers.customer_id , order_status_code [ TEXT ] , order_date [ TEXT ] | Department_Stores : dept_store_id [ INT ] primary_key , dept_store_chain_id [ INT ] Department_Stores.dept_store_chain_id = Department_Store_Chain.dept_store_chain_id , store_name [ TEXT ] , store_address [ TEXT ] , store_phone [ TEXT ] , store_email [ TEXT ] | Departments : department_id [ INT ] primary_key , dept_store_id [ INT ] Departments.dept_store_id = Department_Stores.dept_store_id , department_name [ TEXT ] | Order_Items : order_item_id [ INT ] primary_key , order_id [ INT ] Order_Items.order_id = Customer_Orders.order_id , product_id [ INT ] Order_Items.product_id = Products.product_id | Product_Suppliers : product_id [ INT ] primary_key Product_Suppliers.product_id = Products.product_id , supplier_id [ INT ] Product_Suppliers.supplier_id = Suppliers.supplier_id , date_supplied_from [ TEXT ] , date_supplied_to [ TEXT ] , total_amount_purchased [ TEXT ] , total_value_purchased [ INT ] | Staff_Department_Assignments : staff_id [ INT ] primary_key Staff_Department_Assignments.staff_id = Staff.staff_id , department_id [ INT ] Staff_Department_Assignments.department_id = Departments.department_id , date_assigned_from [ TEXT ] , job_title_code [ TEXT ] , date_assigned_to [ TEXT ] |
-- -- What are the names and genders of staff who have held the title Sales Person, but never Clerical Staff?

SELECT T1.staff_name ,  T1.staff_gender FROM staff AS T1 JOIN Staff_Department_Assignments AS T2 ON T1.staff_id  =  T2.staff_id WHERE T2.job_title_code  =  "Sales Person" EXCEPT SELECT T1.staff_name ,  T1.staff_gender FROM staff AS T1 JOIN Staff_Department_Assignments AS T2 ON T1.staff_id  =  T2.staff_id WHERE T2.job_title_code  =  "Clerical Staff";