Medicamente ce incep cu: afectiunile-tractului-digestiv

QUERY: SELECT p.* FROM produse AS p WHERE (p.Litera_ro = 'afectiunile-tractului-digestiv') AND Vizibil = "Y" ORDER BY p.Name_ro LIMIT -18, 18
ERROR: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '-18, 18' at line 5