-- Sample only: merge deduped staging into curated target
MERGE dbo.Cur_Source AS tgt
USING (
    SELECT SourceId, SourceName, SourceUpdatedUtc
    FROM dbo.Stg_SourceCurated
) AS src
ON tgt.SourceId = src.SourceId
WHEN MATCHED AND (
    ISNULL(tgt.SourceName, '') <> ISNULL(src.SourceName, '') OR
    ISNULL(tgt.SourceUpdatedUtc, '1900-01-01') <> ISNULL(src.SourceUpdatedUtc, '1900-01-01')
)
THEN UPDATE SET
    tgt.SourceName = src.SourceName,
    tgt.SourceUpdatedUtc = src.SourceUpdatedUtc,
    tgt.LastModifiedUtc = SYSUTCDATETIME()
WHEN NOT MATCHED BY TARGET
THEN INSERT (SourceId, SourceName, SourceUpdatedUtc, LastModifiedUtc)
     VALUES (src.SourceId, src.SourceName, src.SourceUpdatedUtc, SYSUTCDATETIME());