Nulls and the MERGE statement: I need to set a value to infinity. How?

Question

In SQL Server 2008, I\'m using MERGE. Everything is fine except that I have 2 nullable columns. If I pass a null value and the target isn\'t null, MERGE doesn\'t see a diffe

Answer 1

Actually, this works better. Just add another substitution value as an OR :-

WHEN MATCHED AND 
    ( 
    NOT (IsNull(tgt.C, 0) = IsNull(src.C, 0)) OR NOT (IsNull(tgt.C, 1) = IsNull(src.C, 1)) 
    ) 
THEN ....

Answer 2

WHEN MATCHED AND
(
   NULLIF(tgt.C, src.C) IS NOT NULL OR NULLIF(src.C, tgt.C) IS NOT NULL
)
THEN

Answer 3

You can use

WHEN MATCHED AND EXISTS (SELECT tgt.C EXCEPT SELECT src.C)

See this article for more on this issue.