MariaDB 10.6

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create table writers( id int, name varchar(200), boss_id int);
insert into writers values( 1,'John',2);
insert into writers values( 2,'Bill',2);
insert into writers values( 3,'Andy',4);
insert into writers values( 4,'Hank',4);
insert into writers values( 5,'Alex',4);
create table papers ( id int, title varchar(200),writer_id int);
insert into papers values( 1,'Boston',1);
insert into papers values( 2,'Chicago',4);
insert into papers values( 3,'Cisco' ,3);
insert into papers values( 4,'Seattle',2);
insert into papers values( 5,'North' ,5);
SELECT * FROM papers p WHERE writer_id in ( select id from writers where boss_id = 4 );


id
title
writer_id


2
Chicago
4

3
Cisco
3

5
North
5


select p.* from papers p 
                inner join writers w on p.writer_id=w.id
where w.boss_id=4


id
title
writer_id


3
Cisco
3

2
Chicago
4

5
North
5