管理器表：

create table Manager(id integer, name varchar(100));
insert into Manager(id, name) values(1, "M1");
insert into Manager(id, name) values(2, "M2");
insert into Manager(id, name) values(3, "M3");

employee表以及manager id（m\ U id）

create table Employee(id integer, m_id integer, name varchar(100));
insert into Employee(id, m_id, name) values(11, 1,"E1");
insert into Employee(id, m_id, name) values(12, 1,"E2");
insert into Employee(id, m_id, name) values(13, 2,"E3");

执行的查询：

select M.id, M.name, count(E.id) from Manager as M, Employee as E where E.m_id=M.id group by E.m_id, M.id, M.name;

输出：

1   M1  2
2   M2  1

预期产量：

1   M1  2
2   M2  1
3   M3  0

请帮助我如何包括m3经理以及分配给他的0名员工？