Mostrar filas dinámicamente como columnas

Oracle 11g y Sql Server 2005+ contienen un comando dinámico que logrará lo que desea.

http://www.orafaq.com/wiki/PIVOT

http://msdn.microsoft.com/en-us/library/ms177410 .aspx

De lo contrario, necesitaría crear una instrucción sql dinámica para lograr esto.

Editar - Aquí tienes (versión de SQL Server).

/* Begin Set up of test data */
IF EXISTS (SELECT 1 from sys.tables WHERE name = N'Item')
    DROP TABLE Item
GO

IF EXISTS (SELECT 1 from sys.tables WHERE name = N'CrossReference')
    DROP TABLE CrossReference
GO


CREATE TABLE Item
(
    Item        varchar(20),
    BasePart    varchar(20),
    Size        varchar(20)
);

CREATE Table CrossReference 
(
    Item        varchar(20),
    CrossReferenceNumber    varchar(20)
);

INSERT INTO Item VALUES ('item1', 'b1', 'Large');
INSERT INTO Item VALUES ('item2', 'bxx1', 'Large');
INSERT INTO Item VALUES ('item3', 'bddf1', 'Small');
INSERT INTO Item VALUES ('item4', 'be3f1', 'Small');
INSERT INTO Item VALUES ('item5', 'b13vx1', 'Small');

INSERT INTO CrossReference VALUES( 'item1', 'crossRef1')
INSERT INTO CrossReference VALUES('item1', 'crossRef2')
INSERT INTO CrossReference VALUES('item1', 'crossRef3')
INSERT INTO CrossReference VALUES('item1', 'crossRef4')
INSERT INTO CrossReference VALUES('item2', 'crossRef1')
INSERT INTO CrossReference VALUES('item2', 'crossRef1')
INSERT INTO CrossReference VALUES('item3', 'crossRef1')
INSERT INTO CrossReference VALUES('item4', 'crossRef2')
INSERT INTO CrossReference VALUES('item5', 'crossRef5')
INSERT INTO CrossReference VALUES('item5', 'crossRef1')
INSERT INTO CrossReference VALUES('item5', 'crossRef2')
INSERT INTO CrossReference VALUES('item5', 'crossRef3')
/* End of test data setup */

/* Begin of actual query */
DECLARE @xRefs VARCHAR(2000),
        @query VARCHAR(8000)

SELECT @xRefs = STUFF((SELECT DISTINCT '],[' + ltrim(CrossReferenceNumber)
                        FROM CrossReference
                        ORDER BY '],[' + ltrim(CrossReferenceNumber)
                        FOR XML PATH('')
                       ), 1, 2, '') + ']'

SET @query = 
    'SELECT * 
     FROM   Item i
            INNER JOIN 
            (
                SELECT * 
                FROM
                (
                    SELECT Item, CrossReferenceNumber
                    FROM CrossReference
                ) t
                PIVOT   (MAX(CrossReferenceNumber) FOR CrossReferenceNumber IN (' + @xRefs + ')) as pvt

            ) xRefs
                ON i.Item = xRefs.Item
     ORDER BY i.Item'

EXECUTE (@query)
/* end */