[odb-users] Self join WHERE value IS NULL

[Boris Kolpackov]

Hi Tom,

Tom Stoffer <tom at touchsurgery.com> writes:

> #pragma db view query("SELECT employee.name FROM employee LEFT 
>   JOIN employee_down ON employee.name = employee_down.value WHERE 
>   employee_down.value IS NULL")

If you need to test container entries for NULL, then this is the only
way since there is no support for using container elements in query
conditions, yet.

In this particular case it is not clear what the benefit of having
NULL pointers in the container when you could just remove the entry
altogether. In this case I think you would have been able to test
this (i.e., no related objects) using a non-native view.

Boris