Database Error

Query: "SELECT p.id as id, pe.seflink as yazarseflink, pe.name as yazar, p.title, p.tablealias, p.seflink, p.creation, p.detail1, p.description FROM product as p JOIN product_category_items as pci ON pci.p_id = p.id JOIN users as pe ON pe.id = p.people WHERE p.deleted = '0' AND p.status = '0' AND (pe.name LIKE '%Merve Kara%' OR pe.seflink LIKE '%Merve Kara%') GROUP BY p.id ORDER BY p.creation DESC"

Error: 'daireiki_p2020.pe.seflink' isn't in GROUP BY