MySQL 8.0

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create table messages (
  id int,
  en varchar(20),
  type varchar(20),
  company_id int
);

insert into messages values
('1', 'new contract', 'new_contract','1'),
('2', 'new offer', 'new_offer','2'),
('3', 'new offer', 'new_offer',NULL),
('4', 'new contract', 'new_contract',NULL);

Records: 4  Duplicates: 0  Warnings: 0


select type, max(company_id) as company_id
from messages
where company_id = 1 or company_id is null
group by type


type
company_id


new_contract
1

new_offer
null


select m.*
from messages m
inner join (
  select type, max(company_id) as company_id
  from messages
  where company_id = 1 or company_id is null
  group by type
) as s on s.type = m.type and s.company_id <=> m.company_id


id
en
type
company_id


1
new contract
new_contract
1

3
new offer
new_offer
null