(Cluster environments only) Returns the name for the Adaptive Server whose id you provide, or the name of the Adaptive Server from which it is issued if you do not provide a value for id.
instance_name([id])
is the ID of the Adaptive Server whose name you are researching.
Returns the name of the instance with an ID of 12:
select instance_name(12)
ANSI SQL – Compliance level: Transact-SQL extension.
Any user can execute instance_name.