Esper EQL check if attribute is set

Question

Let's say we have the following statement:

String STATEMENT =
            "SELECT" +
                    " l.address.locality," +
            " FROM" +
                    " Location AS l";

There could be the case now that address is null. How can I tell Esper not to inform my subscriber in this case?

Answer 1

SELECT address.locality FROM Location(address is not null)