MariaDB 10.6

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select version();


version()


10.6.9-MariaDB-1:10.6.9+maria~deb11


create table channel_titles (
  entry_id int,
  title varchar(10),
  expiration_date int(11) default 0
  );

insert into channel_titles
values
(1, 'test1', 1695513600),
(2, 'test2',  0),
(3, 'test3', 1662768000)
SELECT *, 
  (CASE WHEN expiration_date = 0 THEN CURDATE() + INTERVAL 1 DAY ELSE FROM_UNIXTIME(expiration_date, '%Y-%m-%d') END) AS expiration_date_date 
  FROM channel_titles


entry_id
title
expiration_date
expiration_date_date


1
test1
1695513600
2023-09-24

2
test2
0
2022-09-15

3
test3
1662768000
2022-09-10


SELECT 
  a.entry_id, 
  a.title,
  a.expiration_date
  FROM
     (SELECT 
      entry_id, 
      title, 
      (CASE WHEN expiration_date = 0 THEN CURDATE() + INTERVAL 1 DAY ELSE FROM_UNIXTIME(expiration_date, '%Y-%m-%d') END) AS expiration_date
      FROM channel_titles
     ) a
  WHERE CURDATE() < a.expiration_date


entry_id
title
expiration_date


1
test1
2023-09-24

2
test2
2022-09-15


WITH cte AS (SELECT 
             entry_id, 
             title, 
            (CASE WHEN expiration_date = 0 THEN CURDATE() + INTERVAL 1 DAY ELSE FROM_UNIXTIME(expiration_date, '%Y-%m-%d') END) AS expiration_date
             FROM channel_titles)
  SELECT 
      entry_id, 
      title, 
      expiration_date
      FROM cte
  WHERE CURDATE() < expiration_date


entry_id
title
expiration_date


1
test1
2023-09-24

2
test2
2022-09-15


SELECT 
  entry_id, 
  title, 
  (CASE WHEN expiration_date = 0 THEN CURDATE() + INTERVAL 1 DAY ELSE FROM_UNIXTIME(expiration_date, '%Y-%m-%d') END) AS expiration_date
  FROM channel_titles
WHERE CURDATE() < (CASE WHEN expiration_date = 0 THEN CURDATE() + INTERVAL 1 DAY ELSE FROM_UNIXTIME(expiration_date, '%Y-%m-%d') END)


entry_id
title
expiration_date


1
test1
2023-09-24

2
test2
2022-09-15

entry_id	title	expiration_date	expiration_date_date
1	test1	1695513600	2023-09-24
2	test2	0	2022-09-15
3	test3	1662768000	2022-09-10