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Distributed Queries on Multiple Instances of SQL Server

Specifying an instance of SQL Server on a server running multiple instances of SQL Server requires no syntax changes to the Transact-SQL elements that are used in distributed queries. Instances can be specified in distributed queries by using one of the following methods:

  • Specify a server name by using the syntax 'server_name\instance_name' in the @datasrc parameter of sp_addlinkedserver.

  • Specify 'server=server_name\instance_name' in a connection string.

If an instance is not specified, the distributed query connects to the default instance of SQL Server on the specified server.

The following examples show specifying a specific instance named Payroll on a server named London. (Use SQLNCLI and SQL Server will redirect to the latest version of SQL Server Native Client OLE DB Provider.)

-- Define a linked server on an instance of SQL Server by using @datasrc.
sp_addlinkedserver
    @server = 'LondonPayroll1',
    @srvproduct = ' ',
    @provider = 'SQLNCLI',
    @datasrc = 'London\Payroll'

-- Define a linked server on an instance of SQL Server by using
-- server_name\instance_name in a provider string.
sp_addlinkedserver
    @server = 'LondonPayroll2',
    @srvproduct = ' ',
    @provider = 'SQLNCLI',
    @provstr = 'Server=London\Payroll'

-- Specify an instance of SQL Server in OPENDATASOURCE
-- by using a provider string.
SELECT *
FROM OPENDATASOURCE('SQLNCLI',
    'Data Source=London\Payroll;Integrated Security=SSPI')
    .AdventureWorks2008R2.HumanResources.Employee

-- Specify an instance of SQL Server in OPENROWSET
-- by using a provider string.
SELECT a.*
FROM OPENROWSET(
     'SQLNCLI',
     'Server=London\Payroll;Trusted_Connection=yes',
      AdventureWorks2008R2.HumanResources.Employee) AS a