;
WITH x( a ,
        b ,
        x )
    AS (
    SELECT e1.a ,
           e1.b ,
           e1.c + '(' + STUFF( MAX( a.x ) , 1 , 1 , '' ) + ')' x
      FROM
           @example e1 
		
	 CROSS APPLY( 
        SELECT ',' + CAST( e2.d AS varchar( 5 ))
            FROM @example e2
            WHERE e1.a = e2.a
            AND e1.b = e2.b
            AND e1.c = e2.c
            --group by e2.a
            FOR XML PATH( '' ))a( x )
      GROUP BY e1.a ,
               e1.b ,
               e1.c
    )

    SELECT CAST( a AS varchar( 5 )) + ',''' + b + ''',' + STUFF(
           ( 
             SELECT ',' + x
               FROM x y
               WHERE x.a = y.a
                 AND x.b = y.b
               FOR XML PATH( '' )
           ) , 1 , 1 , '' )
      FROM x
      GROUP BY a ,
               b;