>>Isn't it the same as:
>>

>>UPDATE Relation SET NoField  = CASE WHEN Field = Field.Field
>>                                         THEN Field.Numero
>>                                    ELSE NoField END,
>>                    NoField2 = CASE WHEN Field = Field.Field2
>>                                        THEN Field.Numero
>>                                   ELSE NoField2 END
>>FROM Relation
>>INNER JOIN Field ON (Ralation.Field = Field.Field OR Relation.Field2 = Field.Field2)
>>

>
>Yes, it is, but I want to have it in a loop.

Maybe I'm missing something here, but the loop will slow down the whole operation.