------T-SQL Query to find list of Instances Installed on a machine

----Here is a T-SQL Query to find the list of instances Installed on a machine.
 ------T-SQL Query to find list of Instances Installed on a machine
DECLARE @GetInstances TABLE
( Value nvarchar(100),
 InstanceNames nvarchar(100),
 Data nvarchar(100))

Insert into @GetInstances
EXECUTE xp_regread
  @rootkey = 'HKEY_LOCAL_MACHINE',
  @key = 'SOFTWARE\Microsoft\Microsoft SQL Server',
  @value_name = 'InstalledInstances'

Select InstanceNames from @GetInstances

OR

Create Table #GetInstances
( Value nvarchar(100),
 InstanceNames nvarchar(100),
 Data nvarchar(100))

Insert into #GetInstances
EXECUTE xp_regread
  @rootkey = 'HKEY_LOCAL_MACHINE',
  @key = 'SOFTWARE\Microsoft\Microsoft SQL Server',
  @value_name = 'InstalledInstances'

Select InstanceNames from #GetInstances

drop table #GetInstances