ms sql merge

merge.sql

MERGE targettable AS target
USING
    (
        select id, sub_id, somevalue from sometable_or_query
    )
AS source
ON (target.id = source.id AND target.sub_id = source.sub_id)
WHEN NOT MATCHED BY SOURCE THEN
    DELETE
WHEN MATCHED THEN
    UPDATE SET target.somevalue = source.somevalue
WHEN NOT MATCHED BY target THEN
    INSERT (id,sub_id,somevalue) VALUES (source.id, source.sub_id, source.somevalue);