MariaDB 10.3

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select version();


version()


10.3.36-MariaDB-1:10.3.36+maria~deb10-log


create table employee (
Id int,
ManagerId int);

insert into employee values
(1, 3),
(2, 3),
(3, 6),
(4, 7),
(5, 7),
(6, 8),
(7, 6);

select * from employee;

Records: 7  Duplicates: 0  Warnings: 0




Id
ManagerId


1
3

2
3

3
6

4
7

5
7

6
8

7
6


With recursive cte as (
  select id,Managerid from employee
  union all
  select c.Id,e.ManagerId 
  from cte c join employee e 
  on (c.ManagerId=e.Id)
  )

select ManagerId,count(Id) as Count_of_Employees
from cte group by ManagerId


ManagerId
Count_of_Employees


3
2

6
6

7
2

8
7