MySQL 8.0

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CREATE TEMPORARY TABLE numbers 
WITH RECURSIVE 
cte AS ( select 1 as n
   union all
   select n +1
   from cte
   limit 1000 )
SELECT * FROM cte;




create table tbl_users_posts
(id int,
lik varchar(255));

insert into tbl_users_posts values
(1,'10,11,12,13,14,15'),
(2,'10,11,12,13,14,15,45,66,39,45,89');
select * from tbl_users_posts;


id
lik


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

2
10,11,12,13,14,15,45,66,39,45,89


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
order by id asc;
	


id
lik


1
10

1
11

1
12

1
13

1
14

1
15

2
89

2
10

2
45

2
39

2
66

2
45

2
15

2
14

2
13

2
12

2
11