歷年戰績-MS訪問

Question

欣賞幫助，如果有人讓我知道如何acheive「PREVIOUSVALUE」 cloumn在MSACCESS

我存儲在表比「整體」等各種類別的記錄上顯示的下方，基於ID /名稱/辦公/產品/分類組合，我想acheive前值列thorugh的MS Access功能/高效的查詢

ID  Name  Office Product Overall Month   Value Previous 
228  Woodlands london Europe Sales  201106   6 0 
228  Woodlands london Europe Sales  201202   3 6 
228  Woodlands london Europe Sales  201207   4 3 
228  Woodlands london Europe Overall 201106   6 0 
228  Woodlands london Europe Overall 201202   3 6 
228  Woodlands london Europe Overall 201207   4 3 
228  Woodlands london Europe Exetion 201202   6 0 
228  Woodlands london UK  Exetion 201202   6 1 
228  Woodlands london UK  Exetion 201106   1 0 
228  Woodlands london Europe Exetion 201207   6 6 
228  Woodlands london Europe Content 201106   6 0 
228  Woodlands london UK  Content 201106   1 0 
228  Woodlands london Europe Content 201202   3 6 
228  Woodlands london UK  Content 201202   1 1 
228  Woodlands london UK  Content 201207   1 1 
228  Woodlands london Europe Content 201207   4 3 

先謝謝了！

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查詢的結果 - 未如預期這是因爲TOP1功能我猜的，爲如下的圖像正確的輸出低於

ID Name  Office Product Category Date  Month ValuePrevious 
228 Investors london Europe Content 01/06/2011 201106 6 0 
228 Investors london Europe Content 23/02/2012 201202 3 6 
228 Investors london Europe Content 01/07/2012 201207 4 6 

Answer 1

您可以使用子查詢獲得以前的價值。

SELECT tx.id, 
     tx.name, 
     tx.office, 
     tx.product, 
     tx.overall, 
     tx.month, 
     tx.VALUE, 
     tx.previous, 
     Nz((SELECT TOP 1 [value] 
      FROM tablename t 
      WHERE t.id = tx.id 
        AND t.name = tx.name 
        AND t.office = tx.office 
        AND t.product = tx.product 
        AND t.overall = tx.overall 
        AND t.month < tx.month 
      ORDER BY t.month, rnd(t.id) DESC), 0) AS Prev 
FROM tablename tx 
ORDER BY tx.month; 

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基於改變，很稀疏，樣本數據

SELECT tz.id, 
     tz.name, 
     tz.office, 
     tz.product, 
     tz.date, 
     tz.month, 
     tz.VALUE, 
     Nz((SELECT TOP 1 [value] 
      FROM tablename t 
      WHERE t.id = tz.id 
        AND t.name = tz.name 
        AND t.office = tz.office 
        AND t.product = tz.product 
        AND t.date < tz.date 
      ORDER BY t.date DESC), 0) AS Prev 
FROM tablename tz 
ORDER BY tz.date;