table employees:
id | name  | idE
 1 | name1 | 1
 2 | name2 | 2
 3 | name3 | 3

table email:
id | idE | email
 1 | 1   | [email protected]
 2 | 1   | [email protected]
 3 | 2   | [email protected]
 4 | 3   | [email protected]

select e.id, e.name, m.email from employees as e inner join email as m on p.idE = m.idE

id | name  | email
 1 | name1 | [email protected]
 1 | name1 | [email protected]
 2 | name2 | [email protected]
 3 | name3 | [email protected]

select * from (select a, b from T where a > b) as Z

select * from ( select group_concat(a) as a_list from T ) as Z
where a_list like '%Henry%'