Invalid query: SELECT DISTINCT i.id, i.page, i.is_fulltext, i.category_id, i.page_txt, s.number, v.number, v.date_year, i.issue_id, ba.lastname FROM issues_items i LEFT JOIN issues_issues s ON i.issue_id = s.id LEFT JOIN issues_volumes v ON s.volume_id = v.id LEFT JOIN issues_authors a ON i.id = a.item_id LEFT JOIN issues_reviews_books b ON i.id = b.item_id LEFT JOIN issues_authors ba ON b.id = ba.book_id WHERE i.category_id = 4 AND s.status = 'PUBLISHED' AND ((b.author1lastname REGEXP '^[^a-zA-Z]%' OR b.author1lastname = '' OR b.author1lastname IS NULL)) ORDER BY ba.lastname - Line 1: Incorrect syntax near 'REGEXP'