Sergey,

In so many words - Thank's!

>The ELSE in the first example is never executed when SET ANSI_NULLS OFF.

>SELECT #Temp.*,
>   CASE WHEN (#Temp.S1 = #Temp.S2) OR COALESCE(#Temp.S1,#Temp.S2) IS  NULL THEN 1
>        ELSE 2  END AS S3 From #Temp
>

>>

>>-- Example 1
>>SET ANSI_NULLS OFF
>>
>>Declare @x Integer, @y INTEGER
>>SET @y = 0
>>SELECT @x AS S1, @y AS S2, CASE WHEN @x = @y THEN 1 WHEN @x <> @y THEN 2 ELSE NULL END AS S3
>>
>>-- Produces NULL 0 2
>>
>>-- Example 2
>>Create Table #Temp (S1 Int, S2 Int)
>>Insert into #Temp (S1) Values (NULL)
>>Update #Temp Set S2 = 0
>>Select #Temp.*,
>>   CASE WHEN #Temp.S1 = #Temp.S2 THEN 1
>>      WHEN #Temp.S1 <> #Temp.S2 THEN 2
>>      ELSE NULL
>>   END AS S3 From #Temp
>>-- Produces NULL 0 NULL
>>

>>
>>How can I make sure that the Null comparison is as in Example 1?
>>
>>BR