DECLARE device_ip nvarchar 50 SELECT device_ip Hostname FROM TestDB db

	DECLARE @device_ip nvarchar(50)
	SELECT @device_ip = Hostname FROM [TestDB].[dbo].[Sources]
	  WHERE ID = 
	  (
		  SELECT SourceId FROM [TestDB].[dbo].[Channels]
		  WHERE TAG = 
		  (
			  SELECT TOP(1) PARAM2 
			  FROM inserted
		  )
	  )