postgresql - 具有聚合函数的 DISTINCT ON

Question

我想在 Postgres 中为每个用户获得最多视图的项目。这是我到目前为止的代码：

  SELECT DISTINCT ON (user_id)
    project, user_id, COUNT(view_id) views
  FROM
    table_name
  GROUP BY
    user_id
  ORDER BY
    user_id, views DESC, project