sql query help needed

hi

i have 3 tables

1- occupation (occupation_id pk)
2- employee(cpr_number pk, occupation_id fk)
3- school(school_id pk, cpr_number fk)

i want to display all occupation from occupation table for each school if the occupation was filled with an employee display cpr number otherwise display null in the cpr field column

e.g.

school a

head 8888888
vice null
teacher physics 9999999

please help