How to select only the last entry from sql table using linq entity-CodePudding

I have a table where we store announcements that are displayed on-screen during meetings meeting id, now my employer wants me to add a button that sends announcements to all meeting rooms regardless of room id, I am saving such announcements on the table with a bit value of true or false under name IsAll, so now what I wanna know is, how do I select only the last entry on the table which has the Isall value set to true

ID | roomid     | announcement | IsAll
 1 |     1      |    example   |  ....
 2 |     10     |    test      |  true

in this case, I want to get the announcement with id 2

ID | roomid     | announcement | IsAll
 1 |     1      |    example   |false
 2 |     10     |    test      |  true
 3 |     10     |    test      |  false

in this case, I don't want the SQL to return me anything from the table, with that out of the way I tried

            var msg = db.Broadcasts.Where(x => x.IsAll == true).OrderByDescending(x => x.Id).FirstOrDefault();

but it always returns a value that isn't optimal, how can I achieve this? Thanks

CodePudding user response：

So all you need to do is select the last item and check if the IsAll value is true;

public Broadcast GetLastGlobalMessage()
{
  var lastBroadcast = db.Broadcasts.OrderByDescending(x => x.Id).FirstOrDefault();
  if(lastBroadcast !=null && lastBroadcast.IsAll)
    return lastBroadcast;

  return null;
}