select isnull(a.av_tema,'') as Tema, isnull(a.av_contenido,'') as Conenido, isnull(m.MvNombre1,'') as Nombre1 , isnull(m.MvNombre2,'') as Nombre2, isnull(m.MvNombre3,'')as Nombre3, isnull(m.MvApellido1,'') as Apellido1, isnull(m.MvApellido2,'') as Apellido2 from avisos a inner join codsitios c on a.id_sitio = c.cicodsitio inner join maestros m on c.CiCodMaestro = m.MiCodMaestro