Read SQL Services account by TSQL

DECLARE @serviceaccount varchar(100)
EXECUTE master.dbo.xp_instance_regread
N'HKEY_LOCAL_MACHINE',
N'SYSTEM\CurrentControlSet\Services\MSSQLSERVER',
N'ObjectName',
@ServiceAccount OUTPUT,
N'no_output'
SELECT @Serviceaccount as SQLServer_ServiceAccount
set @Serviceaccount =''
EXECUTE master.dbo.xp_instance_regread
N'HKEY_LOCAL_MACHINE',
N'SYSTEM\CurrentControlSet\Services\SQLSERVERAGENT',
N'ObjectName',
@ServiceAccount OUTPUT,
N'no_output'

SELECT @Serviceaccount as SQLAgent_ServiceAccount