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_Department_Assignments ( staff_id VARCHAR, date_assigned_to INTEGER, job_title_code VARCHAR )

### Question ###
What is id of the staff who had a Staff Department Assignment earlier than any Clerical Staff?

### Accurate SQL ###

SELECT staff_id FROM Staff_Department_Assignments WHERE date_assigned_to < (SELECT MAX(date_assigned_to) FROM Staff_Department_Assignments WHERE job_title_code = 'Clerical Staff')