You can use IN operator

  Thread.NoClient IN (44,99,51,...52)

>The following seems to work:
>
>

>SELECT Temp.AddDate,Thread.NoThread,Thread.Title
> FROM (SELECT TOP 10 MIN(Thread.NoThread) AS NoThread,MAX(Thread.AddDate) AS AddDate,MAX(Thread.Numero) AS Numero
> FROM Thread
> INNER JOIN Thread AS Thread2 ON Thread.Numero=Thread2.NoParent
> WHERE Thread.AddDate>ldDate AND Thread.NoParent=0 AND (Thread.NoClient=44 OR Thread.NoClient=99 OR Thread.NoClient=51 OR 
> Thread.NoClient=37 OR Thread.NoClient=10 OR Thread.NoClient=39 OR Thread.NoClient=32 OR Thread.NoClient=41 OR Thread.NoClient=16 OR 
> Thread.NoClient=24 OR Thread.NoClient=50 OR Thread.NoClient=29 OR Thread.NoClient=28 OR Thread.NoClient=33 OR Thread.NoClient=38 OR 
> Thread.NoClient=36 OR Thread.NoClient=35 OR Thread.NoClient=21 OR Thread.NoClient=17 OR Thread.NoClient=5 OR Thread.NoClient=9 OR 
> Thread.NoClient=42 OR Thread.NoClient=52) AND ISNULL(Thread2.Numero)
> GROUP BY Thread.NoThread ORDER BY 2 DESC) Temp
> INNER JOIN Thread ON Temp.NoThread=Thread.Numero
> ORDER BY Temp.AddDate DESC
>

>
>Is there a fastest way to do it?