Как извлечь информацию на основе последней строки

Question

У меня есть такой стол: -

Таблица A

SKU   Code     Bin
--------------------
FA25  A1707    Q890

Таблица B

SeqNo               ID              SKU     Code    Value
20110321001100909   GRADE           FA20    A1707   3
20110321001100909   SIZE            FA20    A1707   25
20110321001100909   COLOR           FA20    A1707   BLACK
20110321001100909   FINISH          FA20    A1707   GF
20110321001101161   GRADE           FA25    A1707   3
20110321001101161   SIZE            FA25    A1707   25
20110321001101161   COLOR           FA25    A1707   BLACK
20110321001101161   FINISH          FA25    A1707   GF
20110817002647812   GRADE           FA20    A1707   1
20110817002647812   SIZE            FA20    A1707   25
20110817002647812   COLOR           FA20    A1707   BLACK
20110817002647812   FINISH          FA20    A1707   AF
20110817002652517   GRADE           FA25    A1707   1
20110817002652517   SIZE            FA25    A1707   25
20110817002652517   COLOR           FA25    A1707   BLACK
20110817002652517   FINISH          FA25    A1707   AF

Я использую этот SQL для извлечения последней информации: -

select a.SKU, a.CODE, a.BIN b.GRADE_1, b.SIZE_1, b.COLOR, b.FINISH
  from TableA as a
left join (select SKU, CODE,
                  MAX (CASE WHEN ID = 'GRADE' THEN VALUE ELSE NULL END) AS GRADE_1,
                  MAX (CASE WHEN ID = 'SIZE' THEN VALUE ELSE NULL END) AS SIZE_1,
                  MAX (CASE WHEN ID = 'COLOR' THEN VALUE ELSE NULL END) AS COLOR,
                  MAX (CASE WHEN ID = 'FINISH' THEN VALUE ELSE NULL END) AS FINISH
             from TableB 
         GROUP by SKU, CODE) as b ON a.SKU = b.SKU and a.CODE = b.CODE
    where a.CODE = 'A1707'

Вывод из вышеприведенного утверждения, который является неправильным, выглядит следующим образом: -

SKU   CODE   BIN   GRADE  SIZE  COLOR  FINISH
----------------------------------------------
FA25  A1707  Q890  3      25    BLACK  GF

Ожидаемый результат должен быть таким (Оценка 1 и Финиш AF): -

SKU   CODE   BIN   GRADE  SIZE  COLOR  FINISH
----------------------------------------------
FA25  A1707  Q890  1      25    BLACK  AF

Как мне этого добиться?

Answer 1

Это:

SELECT a.SKU, a.Code, a.Bin 
     , b.SeqNo, b.ID, b.Value
FROM TableA AS a
  JOIN TableB AS b
    ON  b.SKU   = a.SKU
    AND b.Code  = a.Code
    AND b.SeqNo = ( SELECT MAX(bm.SeqNo)
                    FROM TableB AS bm
                    WHERE bm.SKU = a.SKU
                      AND bm.Code = a.Code
                  )

покажет:

SKU   Code   Bin   SeqNo               ID        Value
-------------------------------------------------------
FA25  A1707  Q890  20110817002652517   GRADE     1
FA25  A1707  Q890  20110817002652517   SIZE      25
FA25  A1707  Q890  20110817002652517   COLOR     BLACK
FA25  A1707  Q890  20110817002652517   FINISH    AF

---

Затем вы можете изменить вышеприведенное, чтобы получить то, что вы хотите (ищите PIVOTING / UNPIVOTING, чтобы найти другие способы достижения того же самого)

SELECT a.SKU, a.Code, a.Bin 
     , MIN( CASE WHEN b.ID = 'GRADE'
                    THEN b.Value
                    ELSE NULL
            END
          ) AS Grade 
     , MIN( CASE WHEN b.ID = 'SIZE'
                    THEN b.Value
                    ELSE NULL
            END
          ) AS Size
     , MIN( CASE WHEN b.ID = 'COLOR'
                    THEN b.Value
                    ELSE NULL
            END
          ) AS Color
     , MIN( CASE WHEN b.ID = 'FINISH'
                    THEN b.Value
                    ELSE NULL
            END
          ) AS Finish
FROM TableA AS a
  JOIN TableB AS b
    ON  b.SKU   = a.SKU
    AND b.Code  = a.Code
    AND b.SeqNo = ( SELECT MAX(bm.SeqNo)
                    FROM TableB AS bm
                    WHERE bm.SKU = a.SKU
                      AND bm.Code = a.Code
                  )
GROUP BY a.SKU, a.Code, a.Bin

покажет:

SKU   Code   Bin   Grade  Size  Color  Finish
----------------------------------------------
FA25  A1707  Q890  1      25    BLACK  AF

---

Другой способ будет:

SELECT ad.SKU, ad.Code, ad.Bin 
     , b1.Value AS Grade 
     , b2.Value AS Size
     , b3.Value AS Color
     , b4.Value AS Finish
FROM
  ( SELECT a.SKU, a.Code, a.Bin
         , ( SELECT MAX(bm.SeqNo)
             FROM TableB AS bm
             WHERE bm.SKU = a.SKU
             AND bm.Code = a.Code
           ) AS MaxSeqNo 
    FROM TableA AS a
  ) AS ad
  LEFT JOIN TableB AS b1
    ON  b1.SKU   = ad.SKU
    AND b1.Code  = ad.Code
    AND b1.SeqNo = ad.MaxSeqNo
    AND b1.ID = 'GRADE'
  LEFT JOIN TableB AS b2
    ON  b2.SKU   = ad.SKU
    AND b2.Code  = ad.Code
    AND b2.SeqNo = ad.MaxSeqNo
    AND b2.ID = 'SIZE'
  LEFT JOIN TableB AS b3
    ON  b3.SKU   = ad.SKU
    AND b3.Code  = ad.Code
    AND b3.SeqNo = ad.MaxSeqNo
    AND b3.ID = 'COLOR'
  LEFT JOIN TableB AS b4
    ON  b4.SKU   = ad.SKU
    AND b4.Code  = ad.Code
    AND b4.SeqNo = ad.MaxSeqNo
    AND b4.ID = 'FINISH'

Answer 2

select a.SKU, a.CODE, a.BIN, b.GRADE, b.SIZE, b.COLOR, b.FINISH 
           /*remove this line if you don't want SeqNo returned */,b.SeqNo
from #TableA a
left outer join
(
      select x.SeqNo, 
          x.SKU as SKU, 
          x.CODE as CODE,
          max(CASE WHEN ID = 'GRADE' THEN [Value] END) as GRADE,
          max(CASE WHEN ID = 'SIZE' THEN [Value] END) as SIZE,
          max(CASE WHEN ID = 'COLOR' THEN [Value] END) as COLOR,
          max(CASE WHEN ID = 'FINISH' THEN [Value] END) as FINISH
      from #TableB x
      inner join
      (
        select SKU, CODE, max(seqno) as SeqNo
        from #TableB
        group by SKU, CODE
      )y on (x.SeqNo = y.SeqNo)
      group by x.SeqNo, x.SKU, x.CODE
)b on (a.SKU = b.SKU AND a.CODE = b.CODE)