> What's the rationale to teach databases as message queues when it requires special querying and updates when there are so many message queues services already

> What's the rationale to teach databases as message queues when it requires special querying and updates when there are so many message queues services already available, easy to use, and standard compliant? If you already need a database for something else, using the DB as a Queue means you don't need to list {mqFlavorOfChoice} as a requirement for new hires. You also don't have to manage that extra infrastructure. Of course, you are putting additional load on the DB. Mind you, I'm speaking of a pub-sub type queue and not a FIFO here. You can do FIFO queues in DB as well of course, it's just not as compelling of a story nowadays. Also way easier to look at and 'poke' a Database queue if you need to. The queries are also not really difficult to write for a general purpose use case.