MySQL 8.0

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create temporary table numbers as (
  select 1 as n
  union select 2 as n
  union select 3 as n
  union select 4 as n
  union select 5 as n
  union select 6 as n
  union select 7 as n
  union select 8 as n
);


create table tbl_users_posts
(id int,
lik varchar(25));

insert into tbl_users_posts values
(1,'10,11,12,13,14,15');
select * from tbl_users_posts;


id
lik


1
10,11,12,13,14,15


select id,
       substring_index( substring_index(lik, ',', n),',', -1) as lik
from tbl_users_posts
join numbers
  on char_length(lik) 
    - char_length(replace(lik, ',', '')) 
    >= n - 1
	


id
lik


1
10

1
11

1
12

1
13

1
14

1
15