[OWL-826][query] refine func getAlerts()
[OWL-826][query] refine func getAlerts()

masato25/open-falcon-backend,masato25/open-falcon-backend,Cepave/open-falcon-backend,masato25/open-falcon-backend,Cepave/open-falcon-backend,Cepave/open-falcon-backend,masato25/open-falcon-backend,masato25/open-falcon-backend,Cepave/open-falcon-backend,masato25/open-falcon-backend,Cepave/open-falcon-backend,Cepave/open-falcon-backend