MERGE SQL Statement

 MERGE MyTargetTable  As target
USING ( SELECT Col1, Col2, Col3
FROM MySourceTable
WHERE MySourceTable.Col1 = SomeCondition and MySourceTable.Col2= SomeCondition
GROUP BY MySourceTable.Col1)Source
ON
(
target.Col1 = Source.Col1
)
WHEN MATCHED BY target OR Col2 <> Source.Col2 OR (Col2 IS NULL AND Source.Col2 IS NULL)
THEN UPDATE
Set Col2= Source.Col2,
Col3 = Source.Col3
WHEN NOT MATCHED BY target AND Col1 = Source.Col1

THEN INSERT

(
Col1,
Col2,
Col3
)
VALUES
(
Source.Col1,
Source.Col2,
Source.Col2,
)
WHEN NOT MATCHED BY SOURCE
THEN DELETE ;