declare @dir nvarchar(4000)
exec master.dbo.xp_regread
N'HKEY_LOCAL_MACHINE',
N'Software\Microsoft\MSSQLServer\Setup',
N'SQLPath',
@dir output
select @dir
> return NULL
exec master.dbo.xp_instance_regread
N'HKEY_LOCAL_MACHINE',
N'Software\Microsoft\MSSQLServer\Setup',
N'SQLPath',
@dir output
select @dir
>return c:\Program Files\Microsoft SQL Server\MSSQL14.MSSQLSERVER\MSSQL