SELECT U.ID,
       U.NAME,
       P.CNT
FROM U,
     (  /* MAX(물품량+ID) */
     SELECT SUBSTRING(MAX(CNT + ID), 1, 5) CNT, /* 물품량 추출 */
            SUBSTRING(MAX(CNT + ID), 6,3)  ID      /* ID 추출 */
     FROM ( /* ID별 물품량 */
           SELECT ID,
                  CAST(COUNT(*) AS CHAR(5)) CNT 

                       /* 자릿수를 맞추기 위해 문자형으로 변환 */
           FROM P
           GROUP BY ID
           )
      ) P
WHERE U.ID = P.ID