MySQL 8.0

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select @@version;


@@version


8.0.22


create table table1(id int, name char(10));
insert into table1 values (11,'Mic'),(22,'Jeff'),(33,'Tom');

create table table2(id int, note char(10),customerid1 int,customerid2 int,customerid3 int);
insert into table2 values(1,'test',11,11,22),(2,'test',null,33,null)
SELECT t.id, note, t1.name as customer1, t2.name as customer2, 
t3.name as customer3
from table2 t
LEFT JOIN table1 t1 ON t.customerId1 = t1.Id
LEFT JOIN table1 t2 ON t.customerId2 = t2.Id
LEFT JOIN table1 t3 ON t.customerId2 = t3.Id


id
note
customer1
customer2
customer3


1
test
Mic
Mic
Mic

2
test
null
Tom
Tom