使用over()函数结合partition by以指定字段分区

SELECT 
  item_id,
  item_name
FROM
  (SELECT 
    item_id,
    item_name,
    sort_item, 
    row_number () over (PARTITION BY item_id ORDER BY sort_item DESC) AS rm 
  FROM
    table_name) AS t
WHERE t.rm = 1