>Hello, I have to build a query from 3 tables:
>

>Table Usuarios:
>IDusuario    Nombre
>1                Charles
>2                George
>
>Table ModAsg:
>Codmodulo Idusuario
>1                1
>2                1
>3                1
>1                2
>
>
>Table Modulos:
>Cod    Modulos
>1        Mymodule1
>2        Mymodule2
>3        Mymodule3
>4        Mymodule4
>

>When I use this query:
>Select Usuario.Nombre, Modulos.Modulo from Usuario, ModAsg, Modulos where Usuario.Idusuario=Modasg.idusuario and Modasg.codmodulo=Modulos.cod and Usuario.idusuario = 2
>
>It displays:
>George and Mymodule1
>
>I need now to show for george the modules that he doesn't have yet, like
>George and Mymodule2, Mymodule3, Mymodule4
>
>How can i do it?

Select Cod, Modulos from Modulos M ;
INNER JOIN ModAsg MA on M.Cod = M.Codmodulo ;
where MA.IDusuario not in  (select IDusuario    from   Usuarios where Nombre = 'George')

If you need to list all people with the modules they don't have, the query would be more complex.