Question

我有如下表所示的表格。我需要获取与每个不同元素的最大日期时间戳对应的值，并使用SQL Server 2005或更高版本将行转换为列。列名值（即列A1，A2，A3是动态的，可根据可用数据而变化）

基表（来自结果查询）

Id  Name    Value   DateTimeStamp
--------------------------------------
1   A1  5   Nov 14 2011 03:12:12:947PM
1   A1  6   Nov 15 2011 03:12:12:947PM
1   A2  7   Nov 14 2011 03:12:12:947PM
1   A2  8   Nov 15 2011 03:12:12:947PM
1   A3  9   Nov 14 2011 03:12:12:947PM
2   A3  10  Nov 15 2011 03:12:12:947PM
2   A1  1   Nov 14 2011 03:12:12:947PM
2   A1  2   Nov 15 2011 03:12:12:947PM
2   A2  3   Nov 14 2011 03:12:12:947PM
2   A2  4   Nov 15 2011 03:12:12:947PM
2   A3  5   Nov 14 2011 03:12:12:947PM
2   A3  6   Nov 15 2011 03:12:12:947PM

期望的输出：

Id  A1  A2  A3
---------------
1   6   8   10
2   2   4   6

Answer 1

您可以使用dynamic crosstab:

执行此操作

SQL Fiddle

DECLARE @sql NVARCHAR(MAX) = ''

SELECT @sql =
'SELECT
    Id' + CHAR(10)

SELECT @sql = @sql +
    ', MAX(CASE WHEN Name = ''' + Name +  ''' THEN Value END) AS ' + QUOTENAME(Name) + CHAR(10)
FROM (SELECT DISTINCT Name FROM tbl) t
ORDER BY Name

SELECT @sql = @sql +
'FROM (
    SELECT *,
        RN = ROW_NUMBER() OVER(PARTITION BY Id, Name ORDER BY DateTimeStamp DESC)
    FROM tbl
) t
WHERE Rn = 1
GROUP BY Id
ORDER BY Id'

EXEC sp_executesql @sql

SQL Server中的数据透视表查询

1 个答案: