>FaultsLog.fkEventsLog have some NULL value
>
>The result is correct because:
>OR with NULL element CAN return true
>AND with NULL return false
>
>Example:
>

>CREATE TABLE #TEST (A INT NULL)
>INSERT INTO #TEST (A) VALUES (1)
>
>SELECT 'YES' WHERE 2 NOT IN (SELECT A FROM #TEST)
>
>INSERT INTO #TEST (A) VALUES (NULL)
>
>SELECT 'NONE' WHERE 2 NOT IN (SELECT A FROM #TEST)
>
>DROP TABLE #TEST
>
>SELECT 'YES' WHERE 2 NOT IN (1)
>SELECT 'NONE' WHERE 2 NOT IN (1,NULL)
>

Very nice explanation!