Erro no SQL: Column 'url' in field list is ambiguous

SQL:

select id_noticia, titulo, description, url, data, texto from site_noticias, site_categorias where (site_categorias.id_categoria = site_noticias.id_categoria) and status = 1 and data <= '2018-04-25 06:28:35' and site_categorias.url = 'assuncao-do-piaui' order by data desc limit 0,20