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 staff ( staff_name VARCHAR, staff_gender VARCHAR, staff_id VARCHAR )
TABLE: CREATE TABLE Staff_Department_Assignments ( staff_id VARCHAR, job_title_code VARCHAR )

### Question ###
Find the name and gender of the staff who has been assigned the job of Sales Person but never Clerical Staff.

### Accurate SQL ###

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"