Not all parameters were used in the SQL statement (Python, MySQL)

The parameter marker is %s not %d.

add_user = """INSERT INTO DB.tbluser 
              (username, department, startyear, currentpos, link) 
              VALUES (%s, %s, %s, %s, %s)"""

Note that the parameter markers used by mysql.connector may look the same as the %s used in Python string formatting but the relationship is only coincidental. Some database adapters like oursql and sqlite3 use ? as the parameter marker instead of %s.