I faced a strange phenomenon today. I ran the below query to Find all requests with waits other than BROKER_RECEIVE_WAITFOR
select * from sys.dm_exec_requests where session_id > 55 and wait_type not like ('BROKER_RECEIVE_WAITFOR')
The query ran fine, But it failed to list any request with No waits, ie with wait_type as NULL(there were quite a lot of running queries without any waits at this time).
Why is this happening, Isn't it supposed to list all records with wait_type not like 'BROKER_RECEIVE_WAITFOR' including Nulls?
I'm running SQL server 2008R2 SP3.