select cs.standard_id,cs.area_code,cs.exu_dept,

regexp_substr(exu_dept, '[^,]+', 1, level) as dept_id

     from ca_stand_exu_dept  cs

  connect by

    id = prior id

     and instr(exu_dept||',', ',', 1, level) > 0

    and prior dbms_random.value is not null;