跟踪T-SQL中每个表列的数据更改

根据下表，我想得到两列每种水果的价格和数量的变化历史。我正在使用MS SQL Server 2012

例如：

第1行和第3行之间的变化是苹果的价格从 10至30，给出下表结果中的第1行。 变化 第二排和第四排之间是香蕉的价格从20涨到了30 数量从2到3，这就给出了表中的第2行和第3行 结果表。 有办法做到这一点吗？有没有一种方法可以有效地做到这一点

源表

+----+---------+--------+--------+---------+
| id | fruit   | price  | qty    | created |
+----+---------+--------+--------+---------+
| 1  | apples  | 10     | 1      | 1/1/16  |
+----+---------+--------+--------+---------+
| 2  | bananas | 20     | 2      | 1/1/16  |
+----+---------+--------+--------+---------+
| 3  | apples  | 30     | 1      | 2/1/16  |
+----+---------+--------+--------+---------+
| 4  | bananas | 30     | 3      | 2/1/16  |
+----+---------+--------+--------+---------+
| 5  | apples  | 30     | 2      | 3/1/16  |
+----+---------+--------+--------+---------+
| 6  | apples  | 30     | 3      | 7/1/16  |
+----+---------+--------+--------+---------+

结果表

+----+----+--------+--------+--------+---------+
| id | fk | col    | oldval | newval | changed |
+----+----+--------+--------+--------+---------+
| 1  | 3  | price  | 10     | 30     | 2/1/16  |
+----+----+--------+--------+--------+---------+
| 2  | 4  | price  | 20     | 30     | 2/1/16  |
+----+----+--------+--------+--------+---------+
| 3  | 4  | qty    | 2      | 3      | 2/1/16  |
+----+----+--------+--------+--------+---------+
| 4  | 5  | qty    | 1      | 2      | 3/1/16  |
+----+----+--------+--------+--------+---------+
| 5  | 6  | qty    | 2      | 3      | 7/1/16  |
+----+----+--------+--------+--------+---------+

这里有一个方法：

;WITH LagCTE AS (
  SELECT  id, fruit, price, qty, created,
          LAG(price) OVER (PARTITION BY fruit 
                           ORDER BY created) AS prevPrice,
          LAG(qty) OVER (PARTITION BY fruit 
                         ORDER BY created) AS prevQty
  FROM mytable
)
SELECT ROW_NUMBER() OVER (ORDER BY changed) AS id,
       fk, col, oldval, newval, changed
FROM (       
  SELECT id AS fk, fruit, 'price' AS col, 
         prevPrice AS oldval, price AS newval, 
         created AS changed
  FROM LagCTE
  WHERE prevPrice <> price

  UNION ALL 

  SELECT id AS fk, fruit, 'qty' AS col, 
         prevQty AS oldval, qty AS newval, 
         created AS changed
  FROM LagCTE
  WHERE prevQty <> qty) AS t

这里有一个方法：

;WITH LagCTE AS (
  SELECT  id, fruit, price, qty, created,
          LAG(price) OVER (PARTITION BY fruit 
                           ORDER BY created) AS prevPrice,
          LAG(qty) OVER (PARTITION BY fruit 
                         ORDER BY created) AS prevQty
  FROM mytable
)
SELECT ROW_NUMBER() OVER (ORDER BY changed) AS id,
       fk, col, oldval, newval, changed
FROM (       
  SELECT id AS fk, fruit, 'price' AS col, 
         prevPrice AS oldval, price AS newval, 
         created AS changed
  FROM LagCTE
  WHERE prevPrice <> price

  UNION ALL 

  SELECT id AS fk, fruit, 'qty' AS col, 
         prevQty AS oldval, qty AS newval, 
         created AS changed
  FROM LagCTE
  WHERE prevQty <> qty) AS t

---

以下答案的前提条件是price和qty具有相同的数据类型，id是一个标识列

第一步是找到变化。您可以通过计算同一水果的所有记录（按其id排序），然后加入后续记录来实现这一点。然后可以取消打印结果并过滤掉未更改的列

WITH
   SourceNumbered AS
      (
         SELECT
               ROW_NUMBER() OVER(PARTITION BY fruit ORDER BY id) AS nr,
               id, fruit, price, qty, created
            FROM
               SourceTable
      ),
   SourceUnpivoted AS
      (
         SELECT
               U.id, U.fk, U.col
            FROM
               (
                  SELECT
                        L.id, R.id AS fk,
                        L.price - R.price AS price,
                        L.qty - R.qty AS qty
                     FROM
                        SourceNumbered L
                        INNER JOIN SourceNumbered R
                           ON R.fruit = L.fruit
                              AND R.nr = L.nr + 1
               ) D
            UNPIVOT (value FOR col IN (price, qty)) U
            WHERE
               value != 0
      )
SELECT
      U.id, U.fk, U.col,
      CASE U.col
         WHEN 'price'
            THEN O.price
         WHEN 'qty'
            THEN O.qty
      END AS oldval,
      CASE U.col
         WHEN 'price'
            THEN N.price
         WHEN 'qty'
            THEN N.qty
      END AS oldval,
      N.created AS changed
   FROM
      SourceUnpivoted U
      INNER JOIN SourceTable O
         ON O.id = U.id
      INNER JOIN SourceTable N
         ON N.id = U.fk;

---

由于不能取消拆分多个列，因此最终选择中的情况是不可避免的。

以下答案的先决条件是价格和数量具有相同的数据类型，id是标识列

第一步是找到变化。您可以通过计算同一水果的所有记录（按其id排序），然后加入后续记录来实现这一点。然后可以取消打印结果并过滤掉未更改的列

WITH
   SourceNumbered AS
      (
         SELECT
               ROW_NUMBER() OVER(PARTITION BY fruit ORDER BY id) AS nr,
               id, fruit, price, qty, created
            FROM
               SourceTable
      ),
   SourceUnpivoted AS
      (
         SELECT
               U.id, U.fk, U.col
            FROM
               (
                  SELECT
                        L.id, R.id AS fk,
                        L.price - R.price AS price,
                        L.qty - R.qty AS qty
                     FROM
                        SourceNumbered L
                        INNER JOIN SourceNumbered R
                           ON R.fruit = L.fruit
                              AND R.nr = L.nr + 1
               ) D
            UNPIVOT (value FOR col IN (price, qty)) U
            WHERE
               value != 0
      )
SELECT
      U.id, U.fk, U.col,
      CASE U.col
         WHEN 'price'
            THEN O.price
         WHEN 'qty'
            THEN O.qty
      END AS oldval,
      CASE U.col
         WHEN 'price'
            THEN N.price
         WHEN 'qty'
            THEN N.qty
      END AS oldval,
      N.created AS changed
   FROM
      SourceUnpivoted U
      INNER JOIN SourceTable O
         ON O.id = U.id
      INNER JOIN SourceTable N
         ON N.id = U.fk;

---

由于您不能取消拆分多个列，因此最终选择中的情况不可避免。

@rickythefox您可以尝试这两种解决方案，并告诉我们它们如何处理您的实际数据。@rickythefox您可以尝试这两种解决方案，并告诉我们它们如何处理您的实际数据。谢谢您的回答！谢谢你的回答！