Dacă foloseşti SQL Server 2005 sau 2008, poţi folosi operatorul PIVOT, astfel:

CREATE TABLE tabel (

      id int PRIMARY KEY,

      timp time NOT NULL,

      param varchar(50) NOT NULL,

      val int NOT NULL,

      UNIQUE (timp, param)

)

 

INSERT INTO tabel VALUES

(1,'00:00:00','param1',20),

(2,'00:00:00','param2',15),

(3,'00:00:00','param3',12),

(4,'00:01:00','param1',47),

(5,'00:01:00','param2',26),

(6,'00:01:00','param3',32),

(7,'00:02:00','param1',65),

(8,'00:02:00','param2',67),

(9,'00:02:00','param3',98)

 

SELECT ROW_NUMBER() OVER (ORDER BY timp) AS id, timp,

      param1, param2, param3

FROM (SELECT timp, param, val FROM tabel) t

PIVOT (SUM(val) FOR param IN (param1,param2,param3)) p

(crearea tabelei şi inserarea datelor e făcută cu sintaxa specifică SQL Server 2008, dar SELECT-ul funcţionează şi în SQL Server 2005).

Dacă ai SQL Server 2000, atunci poţi folosi ceva de genul:

SELECT (SELECT COUNT(DISTINCT b.timp) FROM tabel b WHERE b.timp<=a.timp) AS id,

      timp,

      SUM(CASE WHEN param='param1' THEN val ELSE 0 END) AS param1,

      SUM(CASE WHEN param='param2' THEN val ELSE 0 END) AS param2,

      SUM(CASE WHEN param='param3' THEN val ELSE 0 END) AS param3

FROM tabel a GROUP BY timp

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