1 
ID  State   Name        Department         City
1   O       George      Sales              Phoenix
1   N       George      Sales              Denver
2   O       Michael     Order Process      San diego
2   N       Michael     Marketing          San jose

我遇到了一种情况，我需要将上面的表格值转换为以下格式。（考虑顶行是列名）

ID  Column      OldValue       New Value
1   Department  Phoenix        Denver
2   Department  Order Process  Marketing
2   City        San diego      San jose

即：我需要从表的旧记录和新记录中捕获更改的列值并将它们记录在不同的表中。但问题是我们有很多这样的表，并且每个表的列名和列数都不同.

如果有人提出将不胜感激的解决方案..！

先感谢您。

4

2 回答 2

2

这是你想要的吗？

 ID  Column      OldValue      New Value
 1   City        Phoenix       Denver
 2   Department  Order Process Marketing
 2   City        San Diego     San jose

这是动态代码：

DECLARE @sqlStm varchar(max);
DECLARE @sqlSelect varchar(max);

DECLARE @tablename varchar(200);
SET @tablename = 'testtable';

-- Assume table has ID column and State column.
SET @sqlSelect = ''
SET @sqlStm = 'WITH old AS
(
   SELECT *
   FROM '+@tablename+'
   WHERE State=''O''
), new AS
(
   SELECT *
   FROM '+@tablename+'
   WHERE State=''N''
)';

  DECLARE @aCol varchar(128)
  DECLARE curCols CURSOR  FOR
    SELECT column_name
    FROM information_schema.columns
    WHERE table_name = @tablename
      AND UPPER(column_name) NOT IN ('ID','STATE')

  OPEN curCols
  FETCH curCols INTO @aCol

  WHILE (@@FETCH_STATUS = 0)
  BEGIN
    SET @sqlStm = @sqlStm +
      ', changed'+@aCol+' AS
(
   SELECT n.ID, '''+@aCol+''' AS [Column], o.['+@aCol+'] AS oldValue, n.['+@aCol+'] AS newValue
   FROM new n
   JOIN old o ON n.ID = o.ID AND n.['+@aCol+'] != o.['+@aCol+']
)'
    IF LEN(@sqlSelect) > 0 SET @sqlSelect = @sqlSelect + ' UNION ALL '

    SET @sqlSelect = @sqlSelect + '
SELECT * FROM changed'+@aCol

    FETCH curCols INTO @aCol

  END

  CLOSE curCols
  DEALLOCATE curCols

    SET @sqlSelect = @sqlSelect + '
ORDER BY id, [Column]'


  PRINT @sqlStm+@sqlSelect

  EXEC (@sqlStm+@sqlSelect)

在我的测试中输出以下内容：

WITH old AS
(
   SELECT *
   FROM testtable
   WHERE State='O'
), new AS
(
   SELECT *
   FROM testtable
   WHERE State='N'
), changedName AS
(
   SELECT n.ID, 'Name' AS [Column], o.[Name] AS oldValue, n.[Name] AS newValue
   FROM new n
   JOIN old o ON n.ID = o.ID AND n.[Name] != o.[Name]
), changedDepartment AS
(
   SELECT n.ID, 'Department' AS [Column], o.[Department] AS oldValue, n.[Department] AS newValue
   FROM new n
   JOIN old o ON n.ID = o.ID AND n.[Department] != o.[Department]
), changedCity AS
(
   SELECT n.ID, 'City' AS [Column], o.[City] AS oldValue, n.[City] AS newValue
   FROM new n
   JOIN old o ON n.ID = o.ID AND n.[City] != o.[City]
)
SELECT * FROM changedName UNION ALL 
SELECT * FROM changedDepartment UNION ALL 
SELECT * FROM changedCity
ORDER BY id, [Column]

原答案如下：

我会这样做——因为我认为它比其他可能更快的方式更清晰：

with old as
(
   Select ID, Name,Department,City
   From table1
   Where State='O'
), new as
(
   Select ID, Name,Department,City
   From table1
   Where State='N'
), oldDepartment as
(
   Select ID, 'Department' as Column, o.Department as oldValue, n.Department as newValue
   From new
   join old on new.ID = old.ID and new.Department != old.Department
), oldCity as
(
   Select ID, 'City' as Column, o.City as oldValue, n.City as newValue
   From new
   join old on new.ID = old.ID and new.City != old.City
)
select * from oldDepartment
union all
select * from oldCity

根据许多事情（表和索引的大小等），它实际上可能比使用数据透视或案例或分组更快。这真的取决于你的数据。如果这是一次性的，我会选择最容易理解的。

于 2013-07-19T23:31:23.433 回答
0

最干净的方法可能是取消透视数据，然后使用聚合。这确实需要对每个表进行自定义编码，您可以通过使用某种形式的动态 SQL 来概括这些编码。

对于您的特定示例，以下是如何操作的说明：

select id, col,
       max(case when OldNew = 'Old' then value end) as OldValue,
       max(case when OldNew = 'New' then value end) as NewValue
from ((select ID, OldNew, 'Name' as col, Name as value
       from t
      ) union all
      (select ID, OldNew, 'Department' as col, Department as value
       from t
      ) union all
      (select ID, OldNew, 'City' as col, City as value
       from t
      )
     ) unpvt
group by id, col
having max(value) <> min(value) and max(value) is not null;

这是为了说明目的。unpivot 可以比使用 更有效地完成union all，特别是在有很多扫描时。这是一个更高效的版本，尽管确切的语法取决于数据库：

select id, col,
       max(case when OldNew = 'Old' then value end) as OldValue,
       max(case when OldNew = 'New' then value end) as NewValue
from (select ID, OldNew, cols.col,
             (case when cols.col = 'Name' then Name
                   when cols.col = 'Department' then Department
                   when cols.col = 'City' then City
              end) as value
      from t cross join
           (select 'Name' as col union all select 'Department' union all select 'City') cols
     ) unpvt
group by id, col
having max(value) <> min(value) and max(value) is not null;

这更有效，因为它通常只会扫描您的表一次，而不是像union all版本中那样为每列扫描一次。

在任一版本中，都隐含假设所有列都具有相同的字符类型。这隐含在您要转换的格式中，其中所有值都在单个列中。

于 2013-07-19T23:31:16.543 回答