MySQL 8.0

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CREATE TABLE links
    (`id` int, `title_to_wiki_link` varchar(19))
;
    
INSERT INTO links
    (`id`, `title_to_wiki_link`)
VALUES
    (1, 'title xxxx xxx zzzz'),
    (2, 'text xxxx'),
    (3, 'title yyyyy'),
    (4, 'title'),
    (5, 'yyy'),
    (6, 'zzz')
SELECT l1.*
FROM links l1
LEFT JOIN links l2 ON l2.id != l1.id AND l2.title_to_wiki_link LIKE CONCAT('%', l1.title_to_wiki_link, '%')
WHERE l2.id IS NULL


id
title_to_wiki_link


1
title xxxx xxx zzzz

2
text xxxx

3
title yyyyy