För SQL Server 2005 och senare försök:
;WITH SalesScore AS (
SELECT
s.PK_ID as S_PK
,c.PK_ID AS c_PK
,CASE
WHEN c.PK_ID IS NULL THEN 0
ELSE CASE WHEN s.ServiceId=c.ServiceId THEN 1 ELSE 0 END
+CASE WHEN (s.Address=c.Address AND s.Zip=c.Zip) THEN 1 ELSE 0 END
+CASE WHEN s.EmailAddress=c.EmailAddress THEN 1 ELSE 0 END
+CASE WHEN s.HomePhone=c.HomePhone THEN 1 ELSE 0 END
END AS Score
FROM Sales s
LEFT OUTER JOIN Customers c ON s.ServiceId=c.ServiceId
OR (s.Address=c.Address AND s.Zip=c.Zip)
OR s.EmailAddress=c.EmailAddress
OR s.HomePhone=c.HomePhone
)
SELECT
s.*,c.*
FROM (SELECT
S_PK,MAX(Score) AS Score
FROM SalesScore
GROUP BY S_PK
) dt
INNER JOIN Sales s ON dt.s_PK=s.PK_ID
INNER JOIN SalesScore ss ON dt.s_PK=s.PK_ID AND dt.Score=ss.Score
LEFT OUTER JOIN Customers c ON ss.c_PK=c.PK_ID
REDIGERA Jag hatar att skriva så mycket faktisk kod när det inte fanns något shema, för jag kan faktiskt inte köra det här och vara säker på att det fungerar. Men för att svara på frågan om hur man hanterar band med det senaste transaktionsdatumet, här är en nyare version av ovanstående kod:
;WITH SalesScore AS (
SELECT
s.PK_ID as S_PK
,c.PK_ID AS c_PK
,CASE
WHEN c.PK_ID IS NULL THEN 0
ELSE CASE WHEN s.ServiceId=c.ServiceId THEN 1 ELSE 0 END
+CASE WHEN (s.Address=c.Address AND s.Zip=c.Zip) THEN 1 ELSE 0 END
+CASE WHEN s.EmailAddress=c.EmailAddress THEN 1 ELSE 0 END
+CASE WHEN s.HomePhone=c.HomePhone THEN 1 ELSE 0 END
END AS Score
FROM Sales s
LEFT OUTER JOIN Customers c ON s.ServiceId=c.ServiceId
OR (s.Address=c.Address AND s.Zip=c.Zip)
OR s.EmailAddress=c.EmailAddress
OR s.HomePhone=c.HomePhone
)
SELECT
*
FROM (SELECT
s.*,c.*,row_number() over(partition by s.PK_ID order by s.PK_ID ASC,c.LastTransaction DESC) AS RankValue
FROM (SELECT
S_PK,MAX(Score) AS Score
FROM SalesScore
GROUP BY S_PK
) dt
INNER JOIN Sales s ON dt.s_PK=s.PK_ID
INNER JOIN SalesScore ss ON dt.s_PK=s.PK_ID AND dt.Score=ss.Score
LEFT OUTER JOIN Customers c ON ss.c_PK=c.PK_ID
) dt2
WHERE dt2.RankValue=1