SELECT id, haslo, znaczenie, data FROM sennik WHERE  (haslo LIKE 'L%' OR haslo LIKE 'l%' OR haslo LIKE '£%' OR haslo LIKE '³%' ) ORDER BY haslo ASC

Illegal mix of collations (latin2_general_ci,IMPLICIT) and (utf8mb3_unicode_ci,COERCIBLE) for operation 'like'