I think you can use ISNULL() or COALESCE() as follows (please test this - I'm doing this off the top of my head)
${SQL:Select ISNULL(CircuitID, 'no circuit found') From Interfaces WHERE Interfaces.NodeID = ${NodeID} AND CircuitID IS NOT NULL}
I think you can use ISNULL() or COALESCE() as follows (please test this - I'm doing this off the top of my head)
${SQL:Select ISNULL(CircuitID, 'no circuit found') From Interfaces WHERE Interfaces.NodeID = ${NodeID} AND CircuitID IS NOT NULL}