Hvordan kan jeg vælge det tætteste match i SQL Server 2005?

for SQL Server 2005 og nyere prøv:

;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

REDIGER Jeg hader at skrive så meget faktisk kode, når der ikke var nogen shema givet, fordi jeg faktisk ikke kan køre dette og være sikker på, at det virker. Men for at besvare spørgsmålet om, hvordan man håndterer bånd med den sidste transaktionsdato, er her en nyere version af ovenstående kode:

;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