Tolong Bantu saya, kendala dalam penulisan sintaks SQL JOIN, Count, n case soalnya eror

select manager_id, first_name, last_name,

(select employee_id, count(avg(employee_id),2) as total_subordinate from datasource.job_employee group by employee_id),

AVG(case when salary <= 10000 then manager_id else Null end) as avg_subordinate_salary

from job_employee t1

left join manager t2 on t1.manager_id = t2.manager_id;