Michel,

SELECT * FROM 
   (SELECT TOP 10 * FROM A ORDER BY MyField
   UNION ALL
   SELECT TOP 10 * FROM B ORDER BY AnotherField) as x
ORDER BY CommonField

>I have a select including a UNION, so to join records from two different results.
>
>If I execute each select individually, this works ok on the order.
>
>When they are combined in the UNION, the order is completed mixed up.
>
>Are there any specific guidelines I would need to watch for when doing that?
>
>I have done that before and never saw such reaction. When I execute the same command in SSMS, I do not have the problem. So, it is somekind of relation when being executed with the SQL Client data provider.