Thank you! Great article!

I have question about SCD type 2.

Can we compare all columns in ON clause like this:

MERGE INTO dbo.Client_SCD2 AS DST

USING dbo.Client AS SRC

ON SRC.ID = DST.BusinessKey

AND DST.ClientName=SRC.ClientName

AND DST.Country = SRC.Country

AND DST.Town=SRC.Town

AND DST.Address1=SRC.Address1

AND DST.Address2=SRC.Address2

AND DST.ClientType=SRC.ClientType

AND DST.ClientSize=SRC.ClientSize

and then use

WHEN NOT MATCHED BY SOURCE THEN

UPDATE SET DST.IsCurrent = 0, DST.ValidTo = @Yesterday

rather than having this part of code:

WHEN MATCHED

AND IsCurrent = 1

AND (

ISNULL(DST.ClientName,'') <> ISNULL(SRC.ClientName,'')

OR ISNULL(DST.Country,'') <> ISNULL(SRC.Country,'')

OR ISNULL(DST.Town,'') <> ISNULL(SRC.Town,'')

OR ISNULL(DST.Address1,'') <> ISNULL(SRC.Address1,'')

OR ISNULL(DST.Address2,'') <> ISNULL(SRC.Address2,'')

OR ISNULL(DST.ClientType,'') <> ISNULL(SRC.ClientType,'')

OR ISNULL(DST.ClientSize,'') <> ISNULL(SRC.ClientSize,'')

)