SQLServer - Fix Always-On metrics query for replica_failover_mode and replica_failover_readiness (#17503)

* Fix Always-On metrics query for replica_failover_mode and replica_failover_readiness

* changelog

* better changelog

Author: joelmarcotte

sqlserver/changelog.d/17503.fixed

@@ -0,0 +1 @@
+Fix Always-On metrics query for replica_failover_mode and replica_failover_readiness. Previously the query returned a cartesian product of rows which could result in incorrect metrics in some cases.

sqlserver/datadog_checks/sqlserver/metrics.py

@@ -891,7 +891,7 @@ class SqlAvailabilityReplicas(BaseSqlServerMetric):
                     inner join sys.dm_hadr_database_replica_cluster_states as dhdrcs
                     on ar.replica_id = dhdrcs.replica_id
                     inner join sys.dm_hadr_database_replica_states as dhdrs
-                    on ar.replica_id = dhdrs.replica_id
+                    on ar.replica_id = dhdrs.replica_id and dhdrcs.group_database_id = dhdrs.group_database_id
                     inner join sys.availability_groups as ag
                     on ag.group_id = ar.group_id""".format(
         table=TABLE