>>Sorry, you misunderstood. I wanted you to run both statements in SSMS in order to compare execution plans. It doesn't matter if they both are too quick.
>
>I have run my query and it gives the attached execution plan.
>
>However, yours doesn't take care of the NoMember condition. So, I do not know how to adjust it to obtain the equivalent.

select * from (select T.Numero, T.Title, T.Url, T.AddDate, row_number() 
over (partition by R.NoThread order by R.NoThread) as Row from Thread T LEFT JOIN Reply R on T.NoThread = R.NoThread where T.NoMember = @NoMember) X 
where Row <=10