select A.id as id,A.Descripcion as articulo,A.Marca as marca,A.Modelo as modelo, A.cantidad as cantidadi,sum(E.cantidad) as cantidadu from Articulos as A join Elementos E on E.id_Articulo=A.id group by A.id having sum(E.cantidad) != A.cantidad union select A.id as id,A.Descripcion as articulo,A.Marca as marca,A.Modelo as modelo, A.cantidad as cantidadi,0 from Articulos as A where A.id not in (select id_Articulo from Elementos E) order by articulo; Relación de Descuadres