テーブル構造の操作

これを試してください

CREATE TABLE #table1
  (
     sourceid  INT,
     name      VARCHAR(50),
     value     VARCHAR(50),
     timestamp NUMERIC(10, 2)
  )

INSERT INTO #table1
VALUES      (1,
             'Mark',
             '99%',
             9.00),
            (1,
             'Mark',
             '75%',
             9.30),
            (1,
             'Mark',
             '60%',
             10.00),
            (1,
             'Mark',
             '85%',
             10.30),
            (2,
             'John',
             '50%',
             9.00),
            (2,
             'John',
             '30%',
             9.30),
            (2,
             'John',
             '65%',
             10.00),
            (2,
             'John',
             '79%',
             10.30)

DECLARE @columns NVARCHAR(MAX),
        @sql     NVARCHAR(MAX);

SET @columns = N'';

SELECT @columns += N', p.' + QUOTENAME(timestamp)
FROM   (SELECT DISTINCT p.timestamp
        FROM   #table1 AS p) AS x;

SET @sql = N'
select *from (SELECT *
FROM
(
  SELECT * FROM #table1
) AS j
PIVOT
(
  MAX(VALUE) FOR TIMESTAMP IN ('
           + STUFF(REPLACE(@columns, ', p.[', ',['), 1, 1, '')
           + ')
) AS p)tb
order by tb.sourceid';

EXEC sp_executesql
  @sql;

DROP TABLE #table1