select p.id,p.name,l.lang_id,l.lang_desc
from langages l join people p on p.lang_id=l.lang_id
but this query returned zero records

select p.id,p.name,l.lang_id,l.lang_desc
from langages l join people p
on l.lag_id::varchar like '%,'+p.lang_id::varchar+',%' 

this query given ERROR: operator does not exist: unknown + character varying

select p.id, p.name, l.id, l.descr
from languages l
  join (
    select id, name, regexp_split_to_table(lang_id, ',') as lid
    from people
  ) p on p.lid::integer = l.id

create table languages 
(
  id      int not null primary key,
  descr   varchar
);

create table people 
(
  id     int not null primary key,
  name   varchar
);

create table speaks 
(
   person_id int not null references people, 
   lang_id int not null references languages,
   primary key (person_id, lang_id)
);

insert into languages 
values
(1,'English'),
(2,'Telugu'),
(3,'Hindi');

insert into people 
values
(1,'Apple'),
(2,'Grape');

insert into speaks (person_id, lang_id)
values
(1, 1),
(1, 2),
(2, 3),
(2, 1);

select p.id, p.name, l.id, l.descr
from people p
  join speaks s on s.person_id = p.id
  join languages l on l.id = s.lang_id;